The ways to the trace level analysis in infrared spectroscopy

The future of infrared (IR) spectroscopy as an analytical technique is assured due to its versatility and its numerous advantages; such as the possibility to obtain molecular specific information for virtually any sample in any state with no treatment or minimal sample preparation. However, spectroscopists are not satisfied with relegating IR spectroscopy just to major and minor component analysis and have been looking at analysis at the trace level too. This review is the recognition of the brilliant research performed during the past two decades and the advances achieved in this area, which have made possible the analysis of contaminants at parts per billion (ppb) levels by IR in differen…

Ion mobility spectrometry as a fast analytical tool in benzalkonium chloride homologs determination.

Abstract A novel procedure is proposed for the determination by ion mobility spectrometry (IMS) of C 12 , C 14 and C 16 benzalkonium chloride (BAC) homologs. The proposed method requires minimum sample treatment and the measurement was made in less than one minute. A high sensitivity was obtained for BAC determination by IMS with limit of detection values from 37 to 69 µg L −1 . Accuracy of the proposed methodology was evaluated through the analysis of aqueous and alcoholic samples spiked with BAC at concentration levels from 0.002% to 20% (w/v), providing recovery values from 91% to 104%. BAC was determined in sanitary alcohols, nasal sprays, postharvest products, algaecides, and treated s…

Simultaneous determination of third-generation synthetic cannabinoids in oral fluids using cyclodextrin-silica porous sorbents

Abstract A microporous material made of cyclodextrin units covalently immobilized into a silica network has found an innovative bioanalytical application in the sample clean-up and simultaneous isolation of three synthetic cannabinoids (ADB-CHMICA, MMB-CHMICA, and MDMB-CHMCZCA) from human oral fluid through solid-phase extraction. The subsequent quantitation is carried out using liquid chromatography coupled to fluorescence detection. The optimized experimental procedure gives recoveries ranging from 76% to 96% in oral fluid samples spiked with the studied cannabinoids at the µg L-1 level. High selectivity is obtained through the extraction procedure due to the presence of cyclodextrin in t…

Physicochemistry of the Atmosphere

Amphetamine-type stimulants analysis in oral fluid based on molecularly imprinting extraction

Abstract A methamphetamine-based molecularly imprinted polymer (MIP) has been prepared by bulk polymerization to recognize new psychoactive substances (NPS) of the amphetamine, cathinones and 2C families in oral fluid samples, being the first precedent of a synthetized MIP for the extraction and preconcentration 32 NPS including amphetamine type substances and synthetic cathinones from oral fluids. Pre-polymerization complex and resulting materials were appropriately characterized by infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption-desorption isotherms. Appropriateness of the material for the specific recognition of the target analytes was also evaluated through …

Optimization of transmission near infrared spectrometry procedures for quality control of pesticide formulations

The use of different response functions to be optimized in the frame of the use of near infrared spectrometry for quality control of active principles in agrochemical formulations has been evaluated. Both, simple functions, based on parameters like sensitivity, repeatability, accuracy, signal to noise ratio, limit of detection or sample throughput, and a complex function, considering all the aforementioned aspects, were employed in the development of a new method for Iprodione determination in agrochemicals. Optimization strategies were based on the previous screening of the most important instrumental factors like number of cumulated scans, nominal resolution, mirror velocity and zero fill…

Elemental fingerprint of wines from the protected designation of origin Valencia

Abstract Inductively coupled plasma optical emission (ICP-OES), in combination with different chemometric approaches, has been used to verify the origin of different red wine samples from Utiel-Requena, Jumilla, Yecla and Valencia protected designation of origin (PDO). The ability of multivariate analysis methods, such as hierarchical cluster analysis (HCA), principal component analysis (PCA), classification and regression trees (CARTs) and discriminant analysis (DA), to achieve wine classification from their elemental contents has been investigated. The calculations were performed using 38 variables (contents of Al, Ba, Be, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Gd, Ho, K, La, Li, Lu, Mg,…

Hard cap espresso extraction-stir bar preconcentration of polychlorinated biphenyls in soil and sediments.

Abstract A Nespresso © hard cap espresso machine has been employed for the quantitative extraction of polychlorinated biphenyls (PCBs) from sediments and soils. Sample extraction was performed from five grams of sample in less than 40 s, with 200 mL ethanol 40% (v/v) in water and PCBs were concentrated using stir bar sorptive extraction (SBSE) and determined by thermal desorption-gas chromatography-tandem mass spectrometry (TD-GC-MS-MS). Eleven PCB congeners (28, 52, 77, 80, 81, 101, 118, 138, 153,169, and 180) were determined in soils and sediments with limits of quantification in the 0.03–0.08 ng g −1 range. Extraction efficiency was established by the analysis of soil samples spiked with…

Elemental composition of seasoning products

The elemental composition of seasoning products, like spices garlic and onion, has been reviewed paying special attention to methods proposed in the literature to determine specific elements or as much as possible components of these products which are widespread used in food preservation or food flavouring and can contribute to the intake of both, essential and toxic elements. Sample treatment and metal speciation aspects have been critically revised concerning onion, garlic and pepper (the most commonly studied products).

Metabolism of third generation synthetic cannabinoids using zebrafish larvae.

Synthetic cannabinoids are the second largest group of new psychoactive substances reported by the United Nations Office on Drugs and Crime in the last decade and case reports bring attention to its high potency effects and its severe toxicity, including fatalities. Moreover, synthetic cannabinoids are usually entirely metabolized and metabolic pathways for many new generation synthetic cannabinoids are still unknown. In this study, the metabolism of five third generation synthetic cannabinoids were evaluated using zebrafish (Danio rerio) larvae as 24-hours in vivo model studied within 5 days after fertilization. The studied synthetic cannabinoids were MMB-CHMICA, ADB-CHMICA, ADB-CHMINACA, …

FTIR determination of Aspartame and Acesulfame-K in tabletop sweeteners.

Two different strategies for sweeteners determination in tabletop samples by Fourier transform middle-infrared (FTIR) spectrometry, an off-line and a fully mechanized extraction of Aspartame and Acesulfame-K with different mixtures of chloroform and methanol, have been developed. The off-line method involves the extraction of both active principles by sonication of samples with 25:75 v/v CHCl3/CH3OH and direct measurement of the peak height values at 1751 cm(-1), corrected using a baseline defined at 1850 cm(-1) for Aspartame, and measurement of the peak height at 1170 cm(-1) in the first-order derivative spectra, corrected by using a horizontal baseline established at 1850 cm(-1), for Aces…

An Infrared Method, with Reduced Solvent Consumption, for the Determination of Chlorsulfuron in Pesticide Formulations

A simple method has been developed for the determination of Chlorsulfuron in pesticide formulations by Fourier Transform Infrared (FTIR). Samples were diluted with CHCl3− , and the FTIR spectra of the samples and standards were obtained at a nominal resolution of 4 cm− 1 from 4000 to 900 cm− 1 with the accumulation of 25 scans. Chlorsulfuron determination was based on the measurement of peak area values from 1373 to 1363 cm− 1 which were corrected by use of a two points baseline defined from 1401 to 1302 cm− 1. The limit of detection achieved, which was of the order of 6 µg g− 1, was appropriate for the determination of Chlorsulfuron in commercially available formulations. FTIR results were…

Assessment of temperature effects on beta-aggregation of native and glycated albumin by FTIR spectroscopy and PAGE: relations between structural changes and antioxidant properties.

Abstract Structural modifications of bovine serum albumin (BSA) induced by heating, and the involvement of glycation of albumin in such processing were studied by using Fourier transform infrared spectroscopy (FTIR) and polyacrylamide gel electrophoresis (PAGE). For native BSA, heating treatments gave rise to β structures which were amplified to the detriment of α-helix form, and which were associated with increased aggregation. A very high correlation was obtained between FTIR Amide I band evolution and aggregation rate parameters, showing the contribution of β-form in aggregates formation. We further assessed the effect of glycation on protein sensibility to heating treatments. A reductio…

Flavonoid determination in onion, chili and leek by hard cap espresso extraction and liquid chromatography with diode array detection

Abstract A low cost extraction procedure, based on the use of a hard cap espresso machine, has been developed for the extraction of myricetin, quercetin, luteolin and kaempferol from vegetables by using 50 mL of ethanol in water (80% v/v) in

Analytical methods to determine cocaine contamination of banknotes from around the world

Abstract The presence of cocaine in a significant number of UK pounds (Xxxx), Euros (€) and North American banknotes ($) in general circulation requires appropriate tools to do determinations. This article discusses the-state-of-the-art in the analysis of cocaine on banknotes. We summarize the usual extraction methods of currency samples and compare them, especially with respect to avoiding sample damage. We critically discuss analytical methods, namely gas chromatography (GC) and liquid chromatography (LC), capillary electrophoresis (CE), immunoassay, thermal desorption tandem mass spectrometry (TD-MS2) and ion-mobility spectrometry (IMS). We also review cocaine levels on banknotes around …

Green chromatography for the analysis of foods of animal origin

Abstract The use of green chromatography methods, for the determination of different components and contaminants in foods of animal origin, has been reviewed from a literature update of papers published in the last years, paying special attention to the efforts regarding the reduction and greening of the sample preparatory steps, the use of clean alternative mobile phases, the improvement of stationary phases used in this type of analysis, and the increase of the analytical information obtained from each chromatography run. In general, it can be seen that the efforts to reduce the deleterious side effects of the analytical methods have also been focused on the maintenance, or improvement, o…

Implementing the contamination prevention programs in the pesticide industry by infrared spectroscopy.

Abstract An infrared spectroscopy based methodology has been successfully developed to implement contamination prevention programs in the pesticide industry. Sensitivity of the IR procedure, traditionally considered the Achilles Hell of the technique, has been improved by using a transmission cell with an open upper side, an internal volume of 35 µL and an optical pathlength of 0.5 mm, providing detection limits of 32 mg L−1 for folpet and 48 mg L−1 for cymoxanil. The manufacturing of folpet and cymoxanil was employed as an example and the IR methodology was validated for the implementation of contamination prevention programs in the pesticide industry. The swab test and rinsate method were…

The role of green extraction techniques in Green Analytical Chemistry

Abstract Greening extraction techniques to improve the sensitivity and the selectivity of analytical methods is the sustainable alternative to classical sample-preparation procedures used in the past. In this update, we review the main strategies employed in the scientific literature to reduce deleterious side-effects of extraction techniques. We demonstrate that the evolution of sample-treatment procedures is focused on the simultaneous improvement of the main analytical features of the method and its practical aspects, including the economic case.

Quality control of Metamitron in agrochemicals using Fourier transform infrared spectroscopy in the middle and near range

Abstract Two vibrational spectrometry-based methodologies were developed for Metamitron determination in pesticide formulations. Fourier transform-middle infrared (FT-MIR) procedure was based on the extraction of Metamitron by CHCl 3 and latter determination by peak area measurement between 1556 and 1533 cm −1 , corrected with a two points baseline established from 1572 to 1514 cm −1 . Fourier transform-near infrared (FT-NIR) determination was made after the extraction of Metamitron in acetonitrile and measuring the peak area between 6434 and 6394 cm −1 corrected using a two points baseline defined between 6555 and 6228 cm −1 . Repeatability, as relative standard deviation, of 5 independent…

Near infrared determination of Diuron in pesticide formulations

Abstract A simple, fast and environmentally friendly near infrared (NIR)-based methodology was developed for Diuron determination in pesticide formulations. This methodology was based on the pesticide extraction with acetonitrile and subsequent transmittance measurement determination by peak area measurement between 2021 and 2047 nm, corrected with a single point baseline established at 2071 nm. The repeatability, as relative standard deviation of five independent analysis of a 15.3 mg g −1 Diuron standard was 0.03% and the limit of detection 0.013 mg g −1 . The reagent consumption was clearly reduced in front of a chromatographic reference procedure from 39.1 ml acetonitrile per sample, re…

Empleo de la estrategia puzle de Aronson para fomentar la cooperación en grupos

[EN] The main objective of the present communication was the implementation of an strategy based on the Puzzle of Aronson in the tutorials corresponding to the Food Additives course of the Degree in Science and Food Technology. The competences of students regarding cooperative learning increased using this dynamic and functional methodology. This type of methodologies are easy to apply in heterogeneous groups of students and are easy to adapt to the characteristics of the classroom

Passive exposure to nicotine from e-cigarettes

A procedure based on the use of ion mobility spectrometry (IMS), after liquid-liquid microextraction (LLME), has been successfully employed for the determination of passive exposure to nicotine from cigarette and e-cigarette smoking. Nicotine has been determined in exhaled breath and oral fluids of both, active and passive smokers. The aforementioned studies, made in closed environments, evidenced that the exhaled breath after conventional blend cigarette smoke provides nicotine levels of the order of 220 ng per puff, in the case of experienced smokers, being exhaled only 32 ng in the case of e-cigarettes. On the other hand, the nicotine amount in oral fluids of passive vapers was between 8…

Comparison of two vibrational procedures for the direct determination of mancozeb in agrochemicals.

The direct determination of mancozeb in agrochemicals has been made by diamond attenuated total reflectance (ATR) Fourier transform infrared spectroscopy in the middle range (DATR-MIR) and diffuse reflectance infrared Fourier transform spectroscopy in the near range (DR-NIR) methods using in both cases a previous identification of the samples using a dendrographic classification and an appropriate partial least squares (PLS) calibration established from a set of nine external standards and optimized for each type of sample. It was analyzed a heterogeneous population of 11 samples obtained from the Spanish market, containing different co-formulated products, such as fosetyl-Al, copper oxychl…

In situ derivatization for double confirmation of 2C–C in oral fluids by ion mobility spectrometry

Ion mobility spectrometry (IMS) is a powerful tool to carry out quick and sensitive detection of illicit activities and has been employed for the determination of the psychedelic drug 2,5-dimethoxy-4 chlorophenethylamine (2C–C) in oral fluid samples. Saliva samples were extracted with chloroform and analysed by IMS reaching a limit of detection (LOD) of 14 μg L−1. Nevertheless, IMS has a scarce resolution and selectivity of the method can be often compromised by the presence of potential interferents with similar molecular weights and drift times. Thus, a rapid and in situ derivatization with acetone, to form the corresponding imine, has been proposed in the present study to confirm the pre…

Green strategies for decontamination of analytical wastes

Within the paradigm of green analytical chemistry, we discuss the different options for cleaning analytical wastes in the literature, paying special attention to on-line recycling of solvents, degradation of toxic compounds and trace-element passivation. The objective of this review is to present and to evaluate critically suitable methodologies that can be incorporated into analytical methods in order to reduce or to avoid the generation of toxic wastes, which could cumulate in the laboratory and have to be managed outside, so increasing the risks and the cost of analysis.

Sample preparation strategies for the determination of psychoactive substances in biological fluids

This review focuses on the existing analytical procedures for the determination of new psychoactive substances (NPS) in biological fluids by chromatographic methods. Direct analysis of samples is scarcely employed and most proposed methodologies include a sample pre-treatment in order to remove matrix interferents and, in some cases, pre-concentrate extracts. Current extraction methods for NPS determination in plasma/serum, urine, and oral fluids have been widely discussed, such as liquid-liquid, solid-phase, and micro extraction approaches, highlighting the advantages and drawbacks of the proposed extraction methodologies. Regarding microextraction approaches, techniques like microextracti…

Microvideos como herramienta docente en Química General

[EN] The objective of the present communication is the preparation of short duration videos, less than 2 minutes (microvideos) where the main ideas of the different topics of the subject General Chemistry would be summarized in a fashion way, enhancing the teaching/learningn process.The development of the videos must be done by the students to fix the main concepts of the lectures and to acquire transversal key competences such as collaborative learning, problem solving skills, self-directed learning and organizative and technologic skills.The obtained results can be considered as preliminar reults, because of effectivity has been evaluated qualitatively. To obtain more realistic conclusion…

Recent developments in flow-analysis vibrational spectroscopy

Abstract This review deals with developments in the new century on the use of vibrational spectroscopy techniques for detection in flow-injection analysis (FIA) systems. To provide a picture of the evolution, highlights and future developments in this field, we revisited Fourier transform infrared (FTIR), in the mid-IR and near-IR ranges, and FT-Raman spectrometry applications using different approaches, from classical FIA to modern (sequential injection analysis (SIA) or multicommutation). We used the analytical abstracts database for 2000–06 for the literature search, but we based this review very much on the experience of our team in this field.

On-line vapor-phase generation combined with Fourier transform infrared spectrometry

We present a critical review of on-line vapor-phase generation combined with Fourier transform infrared spectrometry for detection. We discuss different experimental approaches developed for generating the vapor phase based on different principles (e.g., thermal volatilization, acid-base, redox reaction and covalent hydride generation). Using examples of applications, we try to demonstrate the analytical potential of on-line vapor-phase generation in vibrational spectrometry in order to improve the selectivity and the sensitivity of the measurement step and to make environmentally-friendly procedures available for problem solving in the analytical laboratory. We pay special attention to int…

Green Industrial Analysis

Determination of Third-Generation Synthetic Cannabinoids in Oral Fluids.

Abstract A procedure has been developed for the determination of third-generation synthetic cannabinoids in oral fluid samples by using a semi-automated microextraction by packed sorbent (MEPS) procedure and gas chromatography–mass spectrometry (GC–MS) determination. Five synthetic cannabinoids were employed as model compounds 5F-ADB, MMB-CHMICA, THJ-2201, CUMYL-4CN-BINACA and MDMB-CHMCZCA. The most adequate operative conditions for MEPS were evaluated giving quantitative recoveries, from 89 to 124%, in synthetic and field saliva samples spiked with 125 and 250 μg/L of the studied cannabinoids, with the exception of MDMB-CHMCZCA in field saliva samples that provided slightly lower recoverie…

Preliminary results about the breath of passive smokers and vapers based on the use of portable air monitoring devices

Abstract Preliminary studies were made on the effect of both, classical smoking and electronic cigarettes (ECs) vaping, based on the quality of the indoor air and the breath of passive smokers. Portable air monitoring devices were used to evaluate carbon monoxide (CO), carbon dioxide (CO2), particulate materials (PM), formaldehyde and volatile organic compounds (VOCs) in indoor air and breath of active and passive smokers and vapers. As preliminary results, it can be observed that the major part of PMs liberated in classical smoking and ECs vaping correspond to the lowest size, which is the most dangerous for human health. However, the number of smallest PMs formed during vaping is around 5…

Quality Control of Agrochemical Formulations by Diffuse Reflectance near Infrared Spectrometry

A near infrared (NIR)-based methodology has been developed for the determination of 11 pesticides in commercially available formulations. This solvent free, fast and environmentally friendly method was based on the direct measurement of the diffuse reflectance spectra of solid samples, a hierarchical cluster classification and the use of multivariate calibration models to determine each considered active principle in agrochemicals. The proposed partial least squares (PLS) models used for quantification of each compound were built from specific calibration sets composed of nine spectra corresponding to triplicate measurements of a single well characterised commercial sample and two addition…

Determination at low ppm levels of dithiocarbamate residues in foodstuff by vapour phase-liquid phase microextraction-infrared spectroscopy

Abstract A methodology based on the vapour phase (VP) generation of carbon disulphide from non-volatile dithiocarbamate compounds has been developed for determination of pesticide residues in foodstuff at low ppm levels. The method involves a selective reaction combined with liquid phase microextraction (LPME) and transmission infrared measurements. The use of a home made transmission cell improved the detection limits (LOD) compared to the use of attenuated total reflectance measurements by a factor of approximately 80. Using the most appropriate experimental conditions for the CS2 generation and LPME preconcentration, the precision of the methodology, expressed as the relative standard de…

Trace elemental composition of curry by inductively coupled plasma optical emission spectrometry (ICP-OES)

A methodology based on inductively coupled plasma optical emission spectrometry (ICP-OES) after microwave-assisted acid digestion was developed to determine the content of traces elements in curry samples from the Spanish market. The methodology was validated in terms of accuracy by the analysis of citrus and tomato leaf reference materials achieving comparable results with the certified values. The trace metal content of curry samples was compared with data available from previously published reports concerning Indian samples, especially in terms of heavy metal composition, in order to guarantee the quality of the commercially available spices in the European countries. Values found for th…

Uptake and translocation monitoring of imidacloprid to chili and tomato plants by molecularly imprinting extraction - ion mobility spectrometry

Abstract The degradation of imidacloprid in soil and its uptake and translocation to chili and tomato plants was evaluated, as a proof of concept, of the possibilities of the combination of molecularly imprinted polymers (MIPs) and ion mobility spectrometry (IMS) for a fast and sensitive bioprocesses monitoring tool. To do it, a method based on the selective extraction of imidacloprid from soil and plant materials was developed. In the selected conditions, the MIP-IMS procedure provided a recovery of imidacloprid in soil and plant samples from 102 to 114%, for spiked concentration levels from 0.2 to 2.0 μg g−1. Precision of the methodology, expressed as the relative standard deviation (RSD)…

The use of near-infrared spectrometry in the olive oil industry.

The enormous possibilities offered by near-infrared (NIR) spectroscopy for the (on/in/at-line) quality control process of olive fruits, pastes, and oils are summarized throughout this paper. Special attention has been paid to the combination of NIR and chemometric treatments for the on-line analysis of olive fruits and also for the quality parameters evaluation on olive oils and pastes which can enhance the production of a high quality olive oil and the selection of olive fruit with superior properties. The implementation of NIR sensors in olive mills with successful results has also been reviewed and the commercial olive fruit and oil analyzers highlighted.

Pesticide Industries Air Quality

Seafood freshness determination through vapour phase Fourier transform infrared spectroscopy.

Abstract A new vapour-phase manifold has been developed to determine trimethylamine (TMA) in fish and cephalopod samples by Fourier transform infrared (FT-IR) spectroscopy. Samples were treated off-line for 1 h with trichloroacetic acid (TCA), filtered and washed. The obtained extracts were aspirated and alkalinized with NaOH 2.0 M, in an on-line system. TMA was separated from the solution in a gas phase separator and then transported by means of a nitrogen carrier into a home made 10 cm pathlength IR gas cell, where the corresponding FT-IR spectra were acquired by accumulating 30 scans per spectrum with 2 cm−1 nominal resolution. The method was applied to the determination of TMA in natura…

Development and Evaluation of Paper-Based Devices for Iron(III) Determination in an Advanced Undergraduate Laboratory

We describe a paper-based microfluidic device for iron(III) assay in an applied instrumental analysis laboratory. Simple and convenient devices were fabricated by the students using patterning of f...

Green Analytical Chemistry

Selective determination of clenbuterol residues in urine by molecular imprinted polymer—Ion mobility spectrometry

Abstract Clenbuterol is banned for sports use and strictly regulated in livestock industry. In this study, a procedure for the determination of clenbuterol residues in water and urine has been developed using selective supports combined with ion mobility spectrometry (IMS) determination. A molecular imprinted polymer (MIP) was used for efficient clean-up and preconcentration of clenbuterol followed to a dispersive liquid-liquid microextraction (DLLME) in order to improve selectivity and sensitivity of IMS determinations. Quantitative recoveries from 81 to 99% were obtained for water and spiked urine samples using MIP-DLLME-IMS method. A precision of 4.5%, established as the relative standar…

Environmental applications (air)

Abstract The use of solid sorbent-based devices for the monitoring of contaminants in the air is a widespread trend due to its versatility, physicochemical stability, and high enrichment factor. Active and passive sampling strategies have been developed for air monitoring using different materials, such as carbon-based organic polymers and inorganic sorbents. It has been updated in the literature regarding the most recent applications of the use of solid sorbent-based samplers for the monitoring of air in different sites such as rural, urban, industrialized, and indoor areas, including workplace environments for the evaluation of occupational exposure risks.

Development of a simple and low cost device for vapour phase Fourier Transform Infrared spectrometry determination of ethanol in mouthwashes

Abstract A new vapour phase manifold coupled with Fourier Transform Infrared (FTIR) spectroscopy was developed for ethanol determination in mouthwashes. Two microliters of samples were injected, without any previous pre-treatment into a reactor heated at 70 °C, and the vapour phase generated transported to the FTIR spectrometer using a carrier nitrogen flow of 6 ml min−1. FTIR spectra were continuously recorded, as a function of time, by accumulating two scans and employing 8 cm−1 nominal resolution. Analytical measurements for ethanol were made in the range from 1130 to 992 cm−1 with a baseline defined between 1158 and 957 cm−1. After ethanol measurement the carrier flow was increased to 3…

Towards minimization of chlorinated solvents consume in Fourier transform infrared spectroscopy determination of Propamocarb in pesticide formulations.

Abstract A method has been developed for Fourier transform infrared (FTIR) spectroscopy determination of Propamocarb in emulsifiable pesticide concentrate formulations. Five microliter sample was directly injected without any pretreatment in a CHCl 3 stream at 2 mL min −1 into a closed system and the FTIR spectra of sample and standard solutions were obtained using a nominal resolution of 4 cm −1 from 4000 to 900 cm −1 spectral region and accumulating 2 scans per spectrum. Propamocarb determination was based on the measurement of flow injection analysis (FIA) recording height established from FTIR peak area measurements from 1713 to 1703 cm −1 corrected using a baseline defined at 2000 cm −…

Unexpected identification and characterization of a cathinone precursor in the new psychoactive substance market: 3',4'-methylenedioxy-2,2-dibromobutyrophenone.

Abstract 3′,4′-methylenedioxy-2,2-dibromobutyrophenone has been identified and fully characterized in a sample obtained from an anonymous consumer acquired as ketamine through the Internet market. The substance has been deeply characterized by using standard and high performance analytical techniques such as: attenuated total reflectance-infrared spectroscopy, gas chromatography–mass spectrometry, high-resolution mass spectrometry, elemental analysis, and nuclear magnetic resonance, including 1H, 13C, distortionless enhancement by polarization transfer, two dimensional homonuclear 1H-1H correlation spectroscopy, and 1H-13C heteronuclear single-quantum correlation spectra. 3′,4′-methylenedio…

Simultaneous determination of Folpet and Metalaxyl in pesticide formulations by flow injection Fourier transform infrared spectrometry

Fourier transform infrared (FTIR) spectrometric methodology has been developed for the simultaneous determination of Folpet and Metalaxyl in pesticide formulations. The method involves the extraction of both active principles by sonication of the sample with CHCl3 and direct measurement of the absorbance using peak height values at 1798 cm −1 corrected with a baseline defined at 1810 cm −1 for Folpet, and peak area data established from 1677 to 1667 cm −1 corrected using a baseline from 1692 to 1628 cm −1 for Metalaxyl. Limits of detection (3 s) values of 17 and 16 gg −1 were found for Folpet and Metalaxyl, respectively, with results comparable with those found by liquid chromatography with…

Empleo de Socrative para la evaluación del trabajo previo en asignaturas prácticas de laboratorio

[EN] University students of experimental sciences degrees usually go to the laboratory of practices without having prepared the corresponding activity. This fact leads to a poor preparation of them translated into an effective loss of time available for experimentation, and a reduced acquisition of knowledge and skills, among other aspects. In order to solve this problem, in the present communication, the use of on-line questionnaires using the Socrative platform is described to be used as a prior evaluation system to access the laboratory. The results obtained show that the proposed didactic strategy significantly improves the preparation of the students upon arrival to the laboratory, as …

Pollutants and Air Pollution

Univariate near infrared methods for determination of pesticides in agrochemicals

Abstract It has been developed a general strategy for the determination of pesticides in agrochemicals by Fourier transform near infrared (FT-NIR) spectroscopy. The methodology is based on previous extraction of the active principles through sonication with acetonitrile and direct determination by transmission measurements, using glass vials as measurement cells and univariate calibration at selected wavenumbers as a function of the pesticide to be analyzed. Chlorsulfuron, metamitron, iprodione, pirimicarb, procymidone and tricyclazole were used as test molecules and data obtained by FT-NIR for 20 samples containing one of these active principles compare well with those found by reference l…

Green Solvents for Analytical Separation and Analyses

The alternatives to the use of organic solvents that have been offered by the scientific literature reviewed. In order to look at the best solvents from both analytical and sustainable view points, the use of water under superheated conditions, supercritical fluids, renewable organics, ionic liquids, and aqueous solutions of amphiphillic compounds, have been evaluated. As a general conclusion, it can be seen that, at present, green alternatives to the traditional organic solvents employed in analytical separations and analysis that are being well explored are the capabilities of the use of alcohols, supercritical fluids, and superheated water; and remain unexplored tremendous possibilities …

Partial least squares-near infrared determination of pesticides in commercial formulations

Abstract A solvent free, fast and environmentally friendly near infrared-based methodology (NIR) was developed for pesticide determination in commercially available formulations. This methodology was based on the direct measurement of the diffuse reflectance spectra of solid samples and a multivariate calibration model (partial least squares, PLS) to determine the active principle concentration in commercial formulations. The PLS calibration set was built on using the spiked samples by mixing different amounts of pesticide standards and powdered samples. Buprofezin, Diuron and Daminozide were used as test analytes. Concentration of Buprofezin in the samples was calculated employing a 4-fact…

Attenuated Total Reflection-Fourier transform infrared analysis of the fermentation process of pineapple

Abstract A direct and reagent free procedure has been developed to monitor the fermentation process of pine apple nectar using Attenuated Total Reflectance Fourier-transform mid-infrared spectrometry (FT-IR) and multivariate analysis. A classical 4 2 design for standards was employed for calibration using the information in the spectral range from 907 to 1531 cm −1 of the first order derivative spectra after mean centering of infrared data. The root mean square error of calibration (RMSEC) of 0.040, 0.021, 0.063 and 0.074% w/w were obtained for glucose, fructose, saccharose and ethanol, respectively, and a mean relative validation error of 2.9, 2.1, 2.6 and 3.6% was achieved for glucose, fr…

Non-chromatographic speciation of inorganic arsenic in mushrooms by hydride generation atomic fluorescence spectrometry

Abstract A non-chromatographic speciation method has been developed for the determination of inorganic arsenic in cultivated and wild mushroom samples from different origins. The ultrasound-assisted extraction of the toxic arsenic species As (III) and As (V) was performed for 10 min with 1 mol l −1 H 3 PO 4 and 0.1% (m/v) Triton X-100. After phase separation the residue was washed with 0.1% (w/v) EDTA and centrifuged. As (III) and As (V) were determined by hydride generation atomic fluorescence spectrometry. Speciation was made using proportional equations corresponding to two different measurement conditions, (i) directly feeding sample extracts diluted with HCl and (ii) after reduction wi…

Determination of the new psychoactive substance dichloropane in saliva by microextraction by packed sorbent – Ion mobility spectrometry

Abstract A simple procedure based on microextraction by packed sorbent (MEPS) has been proposed for the extraction of dichloropane in oral fluids and its determination by ion mobility spectrometry (IMS). Extraction conditions such as type of sorbent (octyl and octadecyl silica), sample pH, number of sample loadings, and elution volume were evaluated to obtain the most appropriate values. Dichloropane was extracted from saliva samples using C8 MEPS, loading with 100 μL sample (adjusted to pH 7) in 4 cycles, washing with 100 μL deionized water, and eluting with 50 μL 2-propanol in 10 cycles. The proposed MEPS procedure has been validated in terms of linearity, accuracy, and precision. A limit…

Ion mobility spectrometry and high resolution mass-spectrometry as methodologies for rapid identification of the last generation of new psychoactive substances

A new drug trafficking trend has been observed in the last years by the introduction in the black market of new psychoactive substances (NPS) in order to difficult competent authority controls. In this study, ion mobility spectrometry (IMS) and high-resolution mass-spectrometry (HRMS) were proposed as vanguard and rearguard methodologies for the rapid identification of the last generation of NPS in seizures. The combined use of IMS and HRMS has been evaluated through the analysis of 24 NPS seized from 2016 to 2018 in Valencia (Spain) to demonstrate the utility of this approach. The characteristic reduced mobility (K0) values for seized NPS were determined and mass-mobility relationships wer…

Mid-infrared and Raman spectrometry for quality control of pesticide formulations

This article deals with recent developments in the use of vibrational spectrometry for the quantitative analysis of active components in commercial pesticide formulations. We review the techniques, such as Fourier transform infrared (FTIR) and FT-Raman spectrometries, and measurement modes, such as stopped flow or flow injection. FTIR is being used increasingly in the determination of pesticides in agrochemical products because of its relatively short analysis time. However, FT-Raman spectrometry provides direct analysis of solid and aqueous samples. It is therefore clear that these techniques enable fast, non-destructive, precise and accurate measurements, so vibrational spectrometry appea…

Speciation analysis of food

Analysis of Caffeine, Sweeteners, and Other Additives in Beverages by Vibrational Spectroscopy

This chapter presents a review of the scientific literature on the use of vibrational spectroscopy, near-infrared (NIR), mid-infrared (mid-IR), and Raman, for the analysis of caffeine, sweeteners, and other additives in beverages and related products. Direct analysis procedures of coffee and tea, for both classification according to precedence or variety and quantitative determination of caffeine, are available. For beverage analysis, caffeine has been determined by direct attenuated total reflection (ATR) measurement or by transmission spectroscopy in the mid-IR region after extraction with chloroform. Different strategies have been employed for the analysis of sweeteners in beverages and …

Tuning the selectivity of molecularly imprinted polymer extraction of arylcyclohexylamines: From class-selective to specific

Abstract A molecularly imprinted polymer (MIP) has been prepared in presence of 3-hydroxy phencyclidine (3-OH PCP) as template by bulk polymerization using N,N-dimethylformamide, as porogenic solvent, for the selective solid-phase extraction (SPE) of arylcyclohexylamines from oral fluids. Experimental variables of the extraction procedure have been studied in order to increase both, extraction recovery of 3-OH PCP, used as model analyte, and imprinting factor. By modifying the composition of the washing solvent, the selectivity of the MIP extraction procedure can be tuned, moving from an arylcyclohexylamine selective method to a 3-OH PCP specific method. The applicability of the synthesized…

Magnetic molecularly imprinted polymers for the selective determination of cocaine by ion mobility spectrometry

Abstract Magnetic molecularly imprinted polymers (MMIPs) were prepared for cocaine recognition by bulk polymerization in the presence of magnetic nanoparticles (MNPs). Two reagents (polyethylene glycol (PEG) and 3-(trimethoxysilyl)propyl methacrylate (V)) were used for MNPs modification. MMIPs were characterized and compared in terms of loading capacity, reusability, accuracy and precision for the extraction of cocaine from saliva samples. It was observed that V-MMIPs gave higher physical stability than PEG-MMIPs. Thus, V-MMIP were used for the analysis of cocaine users saliva. The developed procedure based on ion mobility spectrometry (IMS) provided limits of detection and quantification o…

Effects of oxidative modifications induced by the glycation of bovine serum albumin on its structure and on cultured adipose cells

Non-enzymatic glycosylation (glycation) and oxidative damages represent major research areas insofar as such modifications of proteins are frequently observed in numerous states of disease. Albumin undergoes structural and functional alterations, caused by increased glycosylation during non insulin-dependent diabetes mellitus, which is closely linked with the early occurrence of vascular complications. In this work, we first characterized structural modifications induced by the glycation of bovine serum albumin (BSA). A pathophysiological effect of glycated BSA was identified in primary cultures of human adipocytes as it induces an accumulation of oxidatively modified proteins in these cell…

Analysis of hazardous chemicals by “stand alone” drift tube ion mobility spectrometry: a review

Ion mobility spectrometry (IMS) is a widely used technique based on gas phase ion separation under an electric field by differences in ion mobilities. In the last decade, IMS techniques have received increased attention due to their high operational speed and sensitivity. Currently, there are different IMS devices focused on solving different analytical performances, mainly based on linear drift tube (DT IMS), traveling wave, and field asymmetric waveform ion mobility spectrometers. In this review we summarize the main applications of DT-IMS devices for the determination of semi-volatile hazardous chemicals such as: illegal drugs, pesticides, explosives, chemical warfare agents, and others,…

Non-chromatographic speciation

We evaluate the main strategies for screening trace-element species in most types of sample to establish their strengths and weaknesses, as they offer fast, sensitive and cheaper alternatives to classical methods involving chromatography. We consider the principles of non-chromatographic speciation analysis, based on the different behaviors of chemical species before measurement by atomic and molecular spectrometry and electroanalytical methods, so as to give an update on the literature in this field of research.

Detection and characterization of emerging psychoactive substances by ion mobility spectrometry

Rapid detection and identification of novel psychoactive substances (NPS) continues to present significant analytical challenges to forensic and analytical chemists. Ion mobility spectrometry (IMS) has been traditionally considered as the analytical technique of choice to detect illicit drugs in security points in airports, borderlines and customs. Databases of the reduced mobility (K0 ) values of illicit drugs are available in the scientific literature and they should be completed with data of emerging designer drugs. In this paper, we have evaluated the effect of different measurement conditions and determined the K0 values of an important number of NPS including different families; such …

Gamificación: El concurso como actividad grupal de enseñanza/aprendizaje

[EN] The present study consist of the use of game mechanics to promote the development of applications and activities to stimulate, in an attractive way but without sacrificing the rigor required, the teaching and learning in the subjects of Chemistry and Analytical Chemistry in Chemistry degree.

Analytical Process

Fourier transform infrared spectrometric determination of Malathion in pesticide formulations

Abstract An environmentally friendly methodology has been developed for quality control analysis of emulsifiable concentrate pesticide formulations containing Malathion as active ingredient, using flow injection analysis (FIA)–Fourier transform infrared (FTIR) spectrometry. Five microlitres samples were directly injected into a 3 ml closed FIA manifold, in which 2 ml of CHCl 3 was re-circulated at 1.96 ml min −1 . After homogenisation and sample measurement, 2 μl volumes of a Malathion standard were injected, taking absorbance measurements after each injection. Peak height of the chemigrams, established from peak area values between 1027 and 1017 cm −1 , corrected with a baseline fixed from…

Multicommutation-NIR determination of Hexythiazox in pesticide formulations.

A multicommutated flow-system was designed in order to increase analytical throughput and for controlling thermal effects on the NIR spectra for determination of Hexythiazox in pesticide formulations. An on-line standard addition was carried out showing the versatility and repeatability of multicommutation for the on-line mixing and dilution of solutions. Results obtained for commercial samples were statistically comparable with those obtained by an HPLC-reference method. Multicommutation-NIR allows the analysis of 52 samples per hour, in front of the 30 samples per hour analyzed by the NIR-batch procedure and the 7 samples per hour analyzed by HPLC-reference method.

Direct Analysis of Samples

Dispersive magnetic immunoaffinity extraction. Anatoxin-a determination.

Specific monoclonal antibodies were coupled with magnetic Sepharose-based beads and used, for the first time. The methodology was applied to preconcentrate anatoxin-a from water and the later determination by ion mobility spectrometry (IMS). Dispersive magnetic immunoaffinity (d-MagIA) extraction methodology provided a limit of detection of 0.02μgL-1 and a satisfactory precision with a relative standard deviation lower than 15%. Recoveries were evaluated at 0.5, 1.0 and 5.0μgL-1 anatoxin-a with quantitative values from 91 to 115%. Additionally, isobaric interferences with phenylalanine were completely avoided by the use of the developed d-MagIA extraction coupled to IMS determinations.

Headspace–mass spectrometry determination of benzene, toluene and the mixture of ethylbenzene and xylene isomers in soil samples using chemometrics

A simple and fast method has been developed for the determination of benzene, toluene and the mixture of ethylbenzene and xylene isomers (BTEX) in soils. Samples were introduced in 10 mL standard glass vials of a headspace (HS) autosampler together with 150 microL of 2,6,10,14-tetramethylpentadecane, heated at 90 degrees C for 10 min and introduced in the mass spectrometer by using a transfer line heated at 250 degrees C as interface. The volatile fraction of samples was directly introduced into the source of the mass spectrometer which was scanned from m/z 75 to 110. A partial least squares (PLS) multivariate calibration approach based on a classical 3(3) calibration model was build with m…

Determination of Olive Oil Parameters by Near Infrared Spectrometry

Publisher Summary Near infrared (NIR) covers the region between 780 and 2500 nm, and based on the absorption, transmission or reflection of the light, NIR spectroscopy provides a fast and non-destructive technique which is very useful for the simultaneous determination of several compounds in the same sample. Food NIR spectra comprise broad bands corresponding to overtones and combinations of vibrational modes involving C–H, O–H, and N–H chemical bonds, providing a great amount of information which properly treated by chemometrics is useful for classification and for the quantification of many parameters. The olive oil extraction process starts in the harvesting and transport of olive fruit…

Analysis of ecstasy in oral fluid by ion mobility spectrometry and infrared spectroscopy after liquid-liquid extraction.

We developed and evaluated two different strategies for determining abuse drugs based on (i) the analysis of saliva by ion mobility spectrometry (IMS) after thermal desorption and (ii) the joint use of IMS and infrared (IR) spectroscopy after liquid-liquid microextraction (LLME) to enable the sensitivity-enhanced detection and double confirmation of ecstasy (MDMA) abuse. Both strategies proved effective for the intended purpose. Analysing saliva by IMS after thermal desorption, which provides a limit of detection (LOD) of 160μgL(-1), requires adding 0.2M acetic acid to the sample and using the truncated negative second derivative of the ion mobility spectrum. The joint use of IMS and IR spe…

Fast extraction of cannabinoids in marijuana samples by using hard-cap espresso machines

Abstract A simple, quick and low cost procedure was developed for the extraction of Δ9-tetrahydrocannabinol, cannabidiol, and cannabinol from marijuana samples, based on the use of a hard-cap espresso extraction with 2-propanol. After extraction, cannabinoids were directly determined after appropriate dilution by gas-chromatography-mass spectrometry, reaching a limit of detection from 0.03 to 0.05 mg g−1. Extraction efficiency was evaluated by the comparison of results obtained for seized samples by the proposed method and a reference methodology based on ultrasound-assisted extraction. Moreover, ion mobility was proposed for the rapid and sensitive determination of Δ9-tetrahydrocannabinol …

Searching the most appropriate sample pretreatment for the elemental analysis of wines by inductively coupled plasma-based techniques.

Different sample preparation methods were evaluated for the simultaneous multielement analysis of wine samples by inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). Microwave-assisted digestion in closed vessel, thermal digestion in open reactor, and direct sample dilution were considered for the determination of Li, Be, Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Y, Mo, Cd, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Tl, Pb, and Bi in 12 samples of red wine from Valencia and Utiel-Requena protected designation of origin. ICP-MS allows the determination of 17 elements in most…

Analytical Approaches for the Evaluation of Food Protected Designation of Origin

Abstract The state of the art analytical methodologies used to authenticate the origin and composition of foods will be presented in the frame of the protected designation of origin for European labels. The aforementioned labels guarantee the origin and good production practices in the elaboration of foods for human consumption. Target analytes and analytical procedures, together with the chemometric tools used to discriminate foods from different areas or production methods, will be presented and critically discussed. Examples of some of the most commonly evaluated foods in the scientific literature will be also included.

Direct determination of Mancozeb by photoacoustic spectrometry

Abstract A solvent free, fast and environmentally friendly photoacoustic-infrared-based methodology (PAS-FTIR) was developed for the determination of Mancozeb in agrochemicals. This methodology was based on the direct measurement of the transmittance spectra of solid samples and a multivariate calibration model to determine the active ingredient concentration. The proposed partial least squares (PLS) model was made using nine standards prepared by mixing different amounts of kaolin and Mancozeb, with concentrations between 5.43 and 88.10% (w/w). A hierarchical cluster analysis was made in order to classify the samples in terms of similarity in the PAS-FTIR spectra. From their spectra differ…

Towards an automatic lab-on-valve-ion mobility spectrometric system for detection of cocaine abuse.

A lab-on-valve miniaturized system integrating on-line disposable micro-solid phase extraction has been interfaced with ion mobility spectrometry for the accurate and sensitive determination of cocaine and ecgonine methyl ester in oral fluids. The method is based on the automatic loading of 500μL of oral fluid along with the retention of target analytes and matrix clean-up by mixed-mode cationic/reversed-phase solid phase beads, followed by elution with 100μL of 2-propanol containing (3% v/v) ammonia, which are online injected into the IMS. The sorptive particles are automatically discarded after every individual assay inasmuch as the sorptive capacity of the sorbent material is proven to b…

A validated and fast procedure for FTIR determination of Cypermethrin and Chlorpyrifos.

Abstract A FTIR methodology has been developed for the simultaneous determination of Cypermethrin and Chlorpyrifos in pesticide commercially available formulations. The method involves the extraction of both active principles with CHCl3 and direct measurement of the peak area values between 1747 and 1737 cm−1 corrected with a baseline defined at 2000 cm−1 for Cypermethrin and peak height values established at 1549 cm−1 corrected using a baseline situated at 1650 cm−1 for Chlorpyrifos. The limits of detection achieved were of the order of 0.7 and 0.4% (w/w), and the relative standard deviation 0.4 and 0.2% for Cypermethrin and Chlorpyrifos, respectively. The developed procedure provided stat…

Smart Sorption Materials in Green Analytical Chemistry

The use of smart materials as alternative sorption materials for their use in greening sample preparation has been reviewed. It has been taking into consideration recent advances on the use of natural products, without any modification or purification, for making analyte extraction and pre-concentration and the use of specific materials in solid-phase extraction (SPE) and solid-phase microextraction (SPME) approaches. Inorganic materials, such as metal oxides, alumina-based, silica-based, and carbon-based materials together with biomimetic sorbents such as classical immunosorbents, aptamers, and molecularly imprinted polymers, have been reviewed as examples of these materials, stressing the…

Off-line coupling of multidimensional immunoaffinity chromatography and ion mobility spectrometry: A promising partnership.

The extreme specificity of immunoaffinity chromatography (IAC) columns coupled to the high sensitivity of ion mobility spectrometry (IMS) measurements makes this combination really useful for rapid, selective, and sensitive determination of a high variety of analytes in different samples. The capabilities of the IAC-IMS coupling have been highlighted under three different scenarios: (i) multiclass residue analysis using a single IAC column, (ii) multiclass residue analysis using stacked IAC columns, and (iii) isomer analysis. In the first case, the determination of three strobilurin fungicides - azoxystrobin, picoxystrobin, and pyraclostrobin - in water and strawberry juice was considered, …

The importance of incorporating a waste detoxification step in analytical methodologies

The introduction of a waste detoxification step in the analytical process was highlighted using, as example, the determination of copper in pesticide formulations using electrogravimetry, flame atomic absorption spectroscopy and inductively coupled plasma optical emission spectroscopy. This quantitative study showed the improvement of the previously mentioned analytical methods, from a green perspective, after addition of electrodeposition or neutralization steps to the analytical process. Based on this, the application of the eco-scale and the Green Certificate to the evaluation of these methodologies allows the method to be moved from the B and C classes to the A class.

Trace-element composition and stable-isotope ratio for discrimination of foods with Protected Designation of Origin

We review the literature on authentication of foods with Protected Designation of Origin (PDO) from their trace-element composition or stable-isotope ratios in order to evaluate the state of the art of this field and to identify the main parameters of analytical techniques and chemometric-data treatments that permit accurate discrimination of samples of different geographical origins and with different characteristics.

Mineral content of seasonings, salt and vinegar

HPLC determination of oxadiazon in commercial pesticide formulations

A simple, fast and precise high performance liquid chromatographic (HPLC) procedure has been developed for the determination of oxadiazon in emulsifiable concentrated pesticide formulations. 20 µL of diluted sample in acetonitrile were injected in a Kromasil C18 (250 ×am injetados em uma coluna Kromasil C18 4.6 mm, 5 µm) column, using acetonitrile:water (80:20) as mobile phase at 1 mL min-1 flow rate and oxadiazon determined by absorbance measurement at 292 nm. A theoretical limit of detection of 0.02 µg mL-1, a limit of quantification of 0.047 µg mL-1, corresponding to a 0.02 and 0.07% m/v in the original sample, and a relative standard deviation of 0.08% for three replicate analysis of sa…

Ion mobility spectrometry evaluation of cocaine occupational exposure in forensic laboratories

An approach, based on ion mobility spectrometry (IMS) has been developed for the control of cocaine in air of the breathing zone of operators, in laboratory surfaces and in nasal mucus of employees to evaluate cocaine exposure in a forensic laboratory. The analytical methodology has been validated in terms of accuracy, precision and limits of detection and results obtained were statistically comparable with those obtained by liquid chromatography. Cocaine concentration in laboratory air increases from 100 ± 35 ng m(-3) of a normal day to 10,000 ng m(-3) during the manipulation of cocaine seizures. The occupational exposure limit (OEL) for cocaine has not been established which difficult the…

Green extraction techniques in green analytical chemistry

Abstract Green analytical chemistry concept, involving the development of analytical methodologies with an environmental concern, encourages the use of direct analysis to avoid any sample treatment that involves energy and reagent consumption and generation of wastes. However, the determination of target analytes at trace concentration levels or in complex matrices frequently requires previous extraction, pre-concentration, or clean-up steps offering thus, additional possibilities for greening classical methods. So, a green evaluation of alternative extraction techniques to currently used ones for the extraction of solid, liquid, and gaseous samples has been carried out in this study. Moreo…

Molecularly imprinted polymer-based device for field collection of oral fluid samples for cocaine identification.

In this paper, a low-cost, rapid, easy, and potentially portable tool for the identification of cocaine and its semi-quantitative determination in oral fluid has been proposed. A field collection device has been designed, based on a cotton pad with an indicator and a molecularly imprinted polymer (MIP) sorbent, to selective retain cocaine from oral fluid components. After sample collection, cocaine is transferred by using phosphate buffer to the MIP and then eluted with 2-propanol. The obtained extract is analysed by ion mobility spectrometry (IMS), providing a cut-off value of 20 µg L-1 that identifies 100 % true-positive and 95 % true-negative samples. The MIP-IMS procedure has been valid…

Dual mixed-mode poly (vinylpyridine-co-methacrylic acid-co-ethylene glycol dimethacrylate)-based sorbent for acidic and basic drug extraction from oral fluid samples.

Abstract In this study, a dual mixed-mode polymer sorbent was prepared via one-step thermally initiated polymerization of 4-vinylpyridine (VP), methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) for the solid-phase extraction (SPE) of basic and acidic drugs. The use of VP and MAA as ionizable functional monomers allowed the tailoring of ion-exchange and hydrophobic features of the polymer. The obtained polymer was characterized by Fourier-transform infrared spectroscopy and scanning electron microscopy. Next, the retention behavior of dual mixed-mode polymer towards basic and acidic drugs was investigated. Moreover, the practical capability of this novel material was tested f…

Solid sampling Fourier transform infrared determination of Mancozeb in pesticide formulations

Abstract A series of approaches have been assayed for FTIR determination of Mancozeb in several solid commercial fungicides using different calibration strategies. The simplest procedure was based on the use of the ratio between the absorbance of a characteristic band of Mancozeb and that of a KSCN internal standard measured in the FTIR spectra obtained from KBr pellets. It was employed the quotient between peak height absorbance values at 1525 cm−1 for Mancozeb and 2070 cm−1 for KSCN. In these conditions a precision as relative standard deviation (RSD) of 0.6% and a relative accuracy error of 0.8% (w/w) were found. For complex formulations, containing other compounds with characteristic ab…

Geographical traceability of “Arròs de Valencia” rice grain based on mineral element composition

The geographical traceability of rice grain samples involves the use of analytical methodologies that allow their differentiation on the basis of the rice composition, thus confirming their authenticity. In this paper, trace element determination of rice samples by inductively coupled plasma optical emission spectroscopy (ICP-OES) has been addressed to achieve a complete geographical origin classification. Samples (107) from Spain including Valencia, Tarragona, Murcia and Extremadura, Japan, Brazil and India were employed as training set whereas the validation set was formed by 46 samples of the aforementioned geographical origins. Data were processed by linear discriminant analysis (LDA), …

Green Spectroscopy: A Scientometric Picture

ABSTRACT The state of the art of green spectroscopy, as a sustainable and friendly alternative to the classical spectrometric methods of analysis, has been established from the evaluation of the scientific literature published about this topic in the frame of the so-called Green Chemistry paradigm. Special attention has been paid to the fact that keywords like Green Analytical Chemistry, environmentally friendly, or clean analytical method or sustainable analytical chemistry are far from being commonly used in analytical studies. In spite of this fact there are numerous studies that provide direct analytical methodologies, or a reduction of reagents consumption or waste generation, the recy…

First‐Derivative Fourier‐Transform Infrared Determination of Oxadiazon in Commercial Herbicide Formulations

Abstract A Fourier‐transform infrared (FTIR) method has been developed for the quantification of oxadiazon in herbicide formulations. The method involves the extraction of the active ingredient by sonication of the samples with CHCl3 and direct measurement of the peak area values in first‐order derivate spectra from 1770 cm−1 to 1774 cm−1 corrected with a baseline point located at 1950 cm−1 and after a 5‐point smoothing. A limit of detection (3 s) of 0.03 mg g−1 and a typical relative standard deviation (RSD) of 1.3% were found. Results obtained were comparable with those found by liquid chromatography with UV detection. The proposed method involves a 7‐times reduction in solvent consumptio…

Hard Cap Espresso Machines in Analytical Chemistry: What Else?

A hard cap espresso machine has been used in combination with liquid chromatography with molecular fluorescence detection for the determination of polycyclic aromatic hydrocarbons (PAHs) from contaminated soils and sediments providing appropriate extraction efficiencies and quantitative results. Naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benz[b]fluoranthene, benz[k]fluoranthene, benz[a]pyrene, dibenz[a,h]anthracene, benz[ghi]perylene, and indeno[1,2,3-cd]pyrene were used as target compounds. It should be mentioned that the pairs benz[a]anthracene-chrysene and dibenz[a,h]anthracene-benz[ghi]perylene peaks coelute under th…

Development of pipette tip-based poly(methacrylic acid-co-ethylene glycol dimethacrylate) monolith for the extraction of drugs of abuse from oral fluid samples

Abstract In this work, a monolithic polymer based on poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-co-EDMA) was prepared inside 200 μL pipette tips for the extraction of drug of abuse from oral fluid samples. After an appropriate surface tip modification, several polymerization mixtures with different monomer/cross-linker ratios, and percentage of porogen were studied. The most appropriate monolith to easily flow organic solvents and oral fluid samples was prepared with a MAA/EDMA ratio of 8:92 wt/wt and dodecanol containing 10 wt% toluene, as porogenic solvent. Parameters affecting the extraction procedure were evaluated and the monolith was characterized in terms of bindin…

Analysis of drugs including illicit and new psychoactive substances in oral fluids by gas chromatography-drift tube ion mobility spectrometry

Abstract In this study, a gas chromatograph (GC) has been coupled to a drift tube ion mobility spectrometer (IMS) in order to develop an analytical procedure for the determination of psychoactive substances in oral fluids. Working parameters, including the GC-IMS interface ones, were adjusted in order to obtain sensitive and robust signals. A volume of 500 μL of oral fluid was extracted with 250 μL chloroform and, after centrifugation, were injected into the GC-IMS system. Amphetamine, methylone, α-PVP, ketamine, lidocaine, MPHP, cocaine, THJ-2201, and 5F-ADB were employed as model compounds, providing limits of detection from 6 to 15 μg L−1 and recoveries from 70 to 115% for field oral flu…

Trace analysis by ion mobility spectrometry: From conventional to smart sample preconcentration methods. A review.

Ion mobility spectrometry (IMS) is a rapid and high sensitive technique widely used in security and forensic areas. However, a lack of selectivity is usually observed in the analysis of complex samples due to the scarce resolution of the technique. The literature concerning the use of conventional and novel smart materials in the pretreatment and preconcentration of samples previous to IMS determinations has been critically reviewed. The most relevant strategies to enhance selectivity and sensitivity of IMS determinations have been widely discussed, based in the use of smart materials, as immunosorbents, aptamers, molecularly imprinted polymers (MIPs), ionic liquids (ILs) and nanomaterial. …

Sweeteners determination in table top formulations using FT-Raman spectrometry and chemometric analysis

Abstract A partial least squares (PLS) Fourier transform Raman spectrometry procedure based on the measurement of solid samples contained inside standard glass vials, has been developed for direct and reagent-free determination of sodium saccharin and sodium cyclamate in table top sweeteners. A classical 22 design for standards was used for calibration, but this system provides accuracy errors higher than 13% w/w for the analysis of samples containing glucose monohydrate. So, an extended model incorporating glucose monohydrate (23 standards) was assayed for the determination of sodium saccharin and sodium cyclamate in all the samples. Mean centering spectra data pre-treatment has been emplo…

Hard cap espresso extraction and liquid chromatography determination of bioactive compounds in vegetables and spices

Abstract A new analytical procedure, based on liquid chromatography with diode array and fluorescence detection, has been proposed for the determination of bioactive compounds in vegetables and spices after hard cap espresso extraction. This novel extraction system has been tested for the determination of capsaicin and dihydrocapsaicin from fresh chilli and sweet pepper, piperine from ground pepper, curcumin from turmeric and curry, and myristicin from nutmeg. Extraction efficiency was evaluated by using acetonitrile:water and ethanol:water mixtures. The proposed method allows the extraction of samples with 100 mL of 60% (v/v) ethanol in water. The obtained limits of quantification for the …

Mineral content of eggs

Headspace-Liquid Phase Microextraction for Attenuated Total Reflection Infrared Determination of Volatile Organic Compounds at Trace Levels

A combination of headspace (HS) sampling and liquid phase microextraction (LPME) has been successfully developed to solve sensitivity problems in attenuated total reflection (ATR) infrared determination of volatile organic compounds (VOCs). The HS sampling facilitates the selective extraction of the target volatile analytes from the sample matrix, while the liquid phase microextraction allows their preconcentration prior to infrared analysis. The direct determination of extracted analytes in the acceptor solvent provides high preconcentration factors of the order of 200 with a reduced consumption of organic solvents and a minimum generation of wastes, being thus the developed methodology a …

Padlet: el uso de la pizarra colaborativa on-line en estudios de grado

[EN] This communication shows two applications of the padlet virtual board to develop both specific and transversal skills in the study of Degree in Chemistry and Degree in Food Science and Technology. The use of virtual walls allows students to select and expand content related to the subject, as well as facilitate the divulgation and comment of these in a common place to all students of the subject. Finally, data on the utility and degree of satisfaction obtained through an opinion survey were included

Determination of cyromazine in pesticide commercial formulations by vibrational spectrometric procedures

Two vibrational spectrometry-based methodologies were developed for Cyromazine determination in solid pesticide formulations: a Fourier transform infrared (FTIR) procedure, based on the extraction of Cyromazine by CH3OH and direct determination in the extracts by peak height measurement at 1622 cm−1 corrected using a baseline defined at 1900 cm−1, and a FT-Raman determination, made directly on the powdered solid products using standard chromatographic glass vials as sample cells and measuring the Raman intensity between 633 and 623 cm−1 for a baseline established between 663 and 601 cm−1. The sensitivity obtained was 0.01631 absorbance g−1 mg for FTIR determination and 2.23 area values g−1 …

Quantitative Vibrational Spectrometry in the 21st Century: A Scientometric Evaluation

Abstract The state of the art of research on vibrational spectrometry–based quantitative methodologies was evaluated from the literature compiled in Analytical Abstracts from 1980. Medium and near infrared, Raman spectrometry, and photoacoustic methods of analysis were considered. The evolution of the number of published papers, the distribution of the literature as a function of the different application fields in which the vibrational methods were employed, and a study of the impact on this area of chemometric and automation studies clearly shows that, from the 1990s until now, the importance of vibrational spectrometry in application analysis has grown to reach maturity. This field provi…

Development of a simulation chamber for the evaluation of dermal absorption of volatile organic compounds

Abstract An exposition chamber has been designed and developed for the production of contaminated atmospheres with fixed and known concentration of volatile organic compounds. The proposed chamber has been evaluated for the determination of in-vitro diffusion parameters, such as flux and lag time for benzene, toluene, ethylbenzene, and xylenes (BTEX). Polydimethylsiloxane (PDMS) and Strat-M® membranes were evaluated, including the effect of membrane thickness, from 0.5 to 3.0 mm, on the diffusion parameters. The obtained flux values and lag times, ranged from 0.2 to 1.5 μg cm−2 h−1 and from 10 to 130 min, respectively, for studies performed at a BTEX concentration of 51 μg L−1 in air. Diffe…

Solid-phase FT-Raman determination of caffeine in energy drinks

Abstract A solid-phase vibrational spectrometry-based methodology (solid-phase Fourier transform-Raman spectrometry, SP-FT-Raman) has been developed for caffeine determination in commercial energy drink samples. The Raman spectra of caffeine, fixed on a C18 solid phase packed into a glass tube of 5 mm i.d., was obtained directly between 3500 and 70 cm −1 . In order to quantify caffeine, Raman intensity between 573 and 542 cm −1 corrected using a baseline defined between 580 and 540 cm −1 was used. A repeatability of 3%, as relative standard deviation of five analysis of a 200 mg l −1 concentration, and a limit of detection of 18 mg l −1 were obtained. The SP-FT-Raman procedure provides a sa…

Research on Spectroscopy in Morocco from 1984 to 2006

Abstract The evolution of spectroscopy‐based research activity in Morocco was evaluated on the basis of publications that have appeared in the Science Citation Index, Expanded (SCI), during the cumulative period 1984–2006 (September). The most active research groups, and their universities or centers, were identified in this subject from their scientific production in the first years of this century. The preference to publish in specific journals, the main areas of interest to Moroccan authors, and the spectroscopy techniques most commonly employed for their studies were also appraised. This scientometric study was undertaken to introduce a group of papers in a special issue of Spectroscopy…

Determination of non-steroidal anti-inflammatory drugs in water and urine using selective molecular imprinted polymer extraction and liquid chromatography

Abstract A selective solid-phase extraction was employed for the improvement of the determination of non-steroidal anti-inflammatory drugs (NSAIDs) in continental water and urine samples. Ketoprofen, naproxen, diclofenac, and ibuprofen were selected as target analytes due to they are the most frequently administered and consumed NSAIDs. These compounds were extracted using molecular imprinted polymers and determined by liquid chromatography with diode array (DAD), and tandem-mass spectrometry (MS–MS) detectors. Performance of DAD and MS–MS detectors was evaluated throughout this study. The obtained limits of quantification, after a 50-fold preconcentration solid-phase extraction, varied fro…

Identification and determination of synthetic cannabinoids in herbal products by dry film attenuated total reflectance-infrared spectroscopy.

A new procedure has been developed for the identification and quantitative determination of synthetic cannabinoids in illicit herbal preparations. The methodology is based on the use of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) measurement of sample extracts with 2-propanol drying 5µL of the extracts onto the ATR crystal. The qualitative identification was carried out on the 2-propanol extract after identification of the herbal matrix, followed by its subtraction and using a cut-off criterion of 75%. Quantitative determination was made by univariate calibration using the absorbance of the band located at 1520cm-1 of the spectrum. Four different cannabin…

Fourier transform infrared spectrometric strategies for the determination of Buprofezin in pesticide formulations

Abstract Two different strategies for Buprofezin determination, an off-line extraction and stopped-flow determination and an automated procedure, based on the on-line extraction of Buprofezin samples with chloroform and flowing action analysis–fourier transform infrared (FIA–FT-IR) spectrometric measurement of the extracts, have been developed. For the treatment of the off-line extraction mode, data a three-factor partial least squares (PLSs) calibration was developed, using the region from 1465.7 to 1342.3 cm−1 with a single point baseline defined at 2051.9 cm−1 and based on the use of chloroform solutions of Buprofezin. The method provides a R.S.D. On the other hand, the recommended FIA m…

Validated, non-destructive and environmentally friendly determination of cocaine in euro bank notes.

A non-destructive, fast and environmentally friendly procedure has been developed for cocaine determination in euro bank notes. Cocaine was extracted with 15 ml methanol by vortex agitation during 5 min. The extract was evaporated and reconstituted in 0.5 ml methanol. GC-MS-MS analysis was performed using as precursor ion m/z 182.2, with an excitation energy voltage of 1.60 eV, being the product ions measured m/z 150.2 and 82.0. A limit of detection of 0.15 ng per note and a repeatability of 6%, established from the relative standard deviation, of a 1 ng ml(-1) level, were achieved. Recoveries of 101+/-2 and 98+/-3% were obtained for samples spiked with 100 and 10 microg respectively. Resul…

Indoor and outdoor determination of pesticides in air by ion mobility spectrometry.

Abstract The use of ion mobility spectrometry (IMS) has been evaluated as analytical methodology to detect and evaluate the occupational exposure to pesticides. The developed IMS methodology was used, in positive and negative modes, to determine the presence of pesticides in air and to evaluate possible inhalation exposures of workers and users based on active sampling on Teflon membranes and direct thermal desorption IMS. The negative IMS mode was used to determine bensulfuron, clorpyrifos, diniconazole, diuron, flutolanil and imidacloprid, while the positive mode was employed to evaluate formetanate, metalaxyl, metamitrone, metribuzin, paclobutrazol and pirimicarb. The IMS measurements pr…

Development of a molecularly imprinted monolithic polymer disk for agitation-extraction of ecgonine methyl ester from environmental water

Abstract In this study, a new extraction approach based on rotating molecularly imprinted polymer (MIP) disks was developed. The preparation procedure of MIP-disk is simple. Firstly, in order to immobilize MIP onto the surface of polytetrafluoroethylene (PTFE) disk, previous modification and vinylization steps of this fluoropolymer were conducted. Then, MIP synthesis was done by in situ polymerization. The resulting MIP was characterized by Fourier-transform infrared spectroscopy and scanning electron microscopy. Afterwards, two ring magnets were placed in the sides of the MIP-disk to integrate the stirring and preconcentration of sample in just one step. To demonstrate the feasibility of t…

Determination of edible oil parameters by near infrared spectrometry

Abstract A chemometric method has been developed for the determination of acidity and peroxide index in edible oils of different types and origins by using near infrared spectroscopy (NIR) measurements. Different methods for selecting the calibration set, after an hierarchical cluster analysis, were applied. After discrimination of olive oils from maize, seed and sunflower, the prediction capabilities of partial least squares (PLS) multivariate calibration of NIR data were evaluated. Several preprocessing alternatives (first derivative, multiplicative scatter correction, vector normalization, constant offset elimination, mean centering and standard normal variate) were investigated by using…

Vibrational spectroscopy in soil and sediment analysis

The literature concerning the use of vibrational spectroscopy for soil and sediment analysis, published in the last years, has been revised in order to provide a picture of the strengths and weaknesses of these direct techniques to characterize soil composition and properties. Many soil components as water, organic matter, like humic substances, and minerals, can be determined together with physicochemical parameters as pH, conductivity or redox potential. The main strategies to obtain sample spectra and to extract, as many as possible, useful information were evaluated, taking into account the progress on chemometrics and discussing the whole analytical process, from sampling to sample pre…

A review of non-chromatographic methods for speciation analysis.

This manuscript overviews relevant scientific literature concerning speciation of trace elements by using non-chromatographic methods. The main principles of the different strategies proposed in the published works and their advantages and drawbacks are discussed in order to provide to the readers an appropriate picture of the state-of the-art of fast and cheap methodologies available to obtain information about the presence of different chemical forms of trace elements in environmental, clinical and food samples. A selection of the methods proposed for the speciation of the different elements studied was also provided together with their main features.

FTIR approaches for diuron determination in commercial pesticide formulations.

Two strategies have been developed for Diuron determination by FTIR spectrometry, an off-line extraction and stopped-flow determination and a fully mechanized procedure, based on the on-line extraction of Diuron and FIA-FTIR measurement of the extracts. The aforementioned procedures have been compared with a reference chromatographic method. The off-line FTIR spectra were obtained at a nominal resolution of 4 cm(-1) from 4000 to 900 cm(-1) by accumulating 25 scans. Diuron was determined using peak height measurements at 1582 cm(-1) corrected using a baseline defined between 1562 and 1614 cm(-1). The waste generation of the off-line procedure was 3.4 mL chloroform for each sample, and the me…

Adulteration detection of argan oil by inductively coupled plasma optical emission spectrometry

Abstract The singularity of the trace element profile of argan oil has been demonstrated by means of inductively coupled plasma optical emission measurement in combination with different chemometric approaches. The ability of multivariate analysis methods; such as hierarchical cluster analysis (HCA), principal component analysis (PCA), classification trees using Chi -squared Automatic Interaction Detector (CHAID) and discriminant analysis (DA) to achieve edible oils classification based on its type or variety from their elemental content have been investigated. The calculations were performed using 16 variables (contents of Na, Mg, Al, K, Ca, Ti, Fe, Co, Ni, Cu, Zn, Cd, Pr, Sm, Er and Bi at…

Vibrational Spectrometry Strategies for Quality Control of Procymidone in Pesticide Formulations

Abstract Two vibrational spectrometry–based methodologies were developed for procymidone determination in wettable powdered pesticide formulations. The Fourier‐transform infrared (FTIR) procedure was based on the selective extraction of procymidone by chloroform and determination by peak area measurement between 1451 and 1441 cm−1, using a baseline correction established between 1490 and 1410 cm−1, and a precision of 0.4% and a limit of detection of 0.01% w/w procymidone for a sample mass of 25 mg were obtained. For FT‐Raman determination, the selected conditions were peak area measurement between 1005 and 995 cm−1 Raman shift, with a baseline correction fixed between 1030 and 947 cm−1, and…

Comprehensive analysis of airborne pesticides using hard cap espresso extraction-liquid chromatography-high-resolution mass spectrometry

A hard cap espresso extraction procedure has been developed to recover airborne pesticides in particulate matter trapped in filters. This extraction step was made for 20s at 72°C and 19bar using 50mL of 20% (v/v) acetonitrile in water. After that, based on NaCl salting out, extracts were concentrated 22 times and analysed by ultra-high performance liquid chromatography - high resolution mass spectrometry. 35 pesticides were evaluated, as a proof of concept, being validated the whole methodology and compared the extraction method with that based on microwave assisted extraction for 20min. In short, the method avoids cross-contamination of samples, it is relatively fast and consumes only 10mL…

Automated Fourier Transform near Infrared Determination of Buprofezin in Pesticide Formulations

An automated procedure has been developed for Fourier transform near infrared (FT-NIR) determination of buprofezin in pesticide formulations. This methodology is based on on-line pesticide extraction with acetonitrile from solid samples and its determination by using peak area absorbance measurements between 2147 and 2132 nm, corrected with a horizontal baseline established at 2091 nm. The repeatability, as a relative standard deviation of five independent analyses of 18.9 mg g−1 of buprofezin, was 0.06% and the limit of detection 5 mg L−1. The reagent consumption was clearly reduced compared with a chromatographic reference procedure from 40.4 mL acetonitrile per sample, required by high …

Smart materials for sample preparation in bioanalysis: A green overview

Abstract The analysis of biological samples is a complex challenge due to the complexity of the matrix, but also to the low concentration of target analytes that must be determined. Consequently, different sample treatment procedures have been proposed in bioanalysis to clean-up and enrich sample extracts, paying special attention to microextraction approaches. In this frame, the combined use of microextraction approaches with smart materials provides environmentally friendly sample treatment strategies with improved selectivity, sensitivity, and reusability. Applications of smart solid materials includes antibody–antigen interaction based materials, aptamers, molecularly imprinted polymers…

Mid- and near-infrared determination of metribuzin in agrochemicals

Abstract Two infrared-based methodologies were developed for metribuzin determination in pesticide formulations after extraction with acetonitrile. Fourier transform mid infrared (MIR) procedure was based on peak area measurements between 1692 and 1670 cm −1 corrected with a baseline fixed at 1877 cm −1 . Fourier transform near infrared (NIR) determination was made by measuring the peak area between 6498 and 6332 cm −1 corrected using a two points baseline defined between 6570 and 6212 cm −1 . Repeatability, as relative standard deviation, of 5 independent measurements at mg g −1 concentration level was 0.3% and 0.03% for MIR and NIR, respectively, and limit of detection values of 9 and 17 …

Determination of Mercury in Milk by Cold Vapor Atomic Fluorescence: A Green Analytical Chemistry Laboratory Experiment

Green analytical chemistry principles were introduced to undergraduate students in a laboratory experiment focused on determining the mercury concentration in cow and goat milk. In addition to traditional goals, such as accuracy, precision, sensitivity, and limits of detection in method selection and development, attention was paid to the evaluation of green parameters of the analytical methods. Milk samples were evaluated by cold vapor atomic fluorescence spectrometry (CV-AFS) and the wastes were minimized by co-precipitation with Fe(III).

The Challenges of Air Protection and Control

Direct and fast determination of polychlorinated biphenyls in contaminated soils and sediments by thermal desorption-gas chromatography-tandem mass spectrometry

Abstract A direct procedure based on thermal desorption-gas chromatography-tandem mass spectrometry (TD–GC–MS–MS) was developed for the fast extraction of seven polychlorinated biphenyls (PCBs) from sediments and soils. PCBs were directly extracted, from 20 to 75 mg of sample, without any chemical pre-treatment or use of organic solvents, after the addition of 10 µL internal standard (PCB 195) in acetone. Sample treatment was totally automated. PCBs were extracted at 250 °C for 20 min, using a helium flow and the PCBs were trapped in a cryogenic Tenax trap at −10 °C. After that, analytes were directly desorbed at 270 °C and introduced to the GC–MS–MS system. Recoveries were established usin…

Green Analytical Chemistry

We discuss the origins and the fundamentals of Green Analytical Chemistry (GAC), based on the literature published about clean, environmentally-friendly or GAC methods. We pay special attention to the strategies and the tools available to make sample-pretreatment and analytical methods greener. We consider that the main principles are to replace toxic reagents, to miniaturize and to automate methods, making it possible to reduce dramatically the amounts of reagents consumed and wastes generated, so reducing or avoiding side effects of analytical methods. We also consider on-line decontamination or passivation of wastes to be of special interest in making analytical chemistry sustainable.

Cocaine abuse determination by ion mobility spectrometry using molecular imprinting

A cocaine-based molecular imprinted polymer (MIP) has been produced by bulk polymerization and employed as selective solid-phase extraction support for the determination of cocaine in saliva samples by ion mobility spectrometry (IMS). The most appropriate conditions for washing and elution of cocaine from MIPs were studied and MIPs were characterized in terms of analyte binding capacity, reusability in water and saliva analysis, imprinting factor and selectivity were established and compared with non-imprinted polymers. The proposed MIP-IMS method provided a LOD of 18μgL-1 and quantitative recoveries for blank saliva samples spiked from 75 to 500μgL-1 cocaine. Oral fluid samples were collec…

Noninvasive double confirmation of cocaine abuse.

A double confirmation procedure, based on the combined application of Ion Mobility Spectrometry (IMS) and Infrared Spectroscopy (IR), has been developed for the noninvasive unambiguous identification of cocaine consume. The use of nasal mucus as a biological specimen for cocaine abuse confirmation has been proposed as an alternative to the use of blood and urine due to its noninvasive character and the presence of the parent compound instead of its metabolites. Sampling conditions, interferences caused by cutting agents and other substances, and limits of identification (LOI) and confirmation (LOC) have been deeply evaluated. The procedure combines the high sensitivity of the IMS to identif…

Carbon-Based Nanomaterials in Analytical Chemistry

Smart Materials for Forensic Analysis

Methylone determination in oral fluid using microextraction by packed sorbent coupled to ion mobility spectrometry

Abstract A methodology based on microextraction by packed sorbent (MEPS) followed by ion mobility spectrometry (IMS) has been developed for the simple and automated determination of methylone in oral fluids. MEPS was carried out using a 100 µL eVol® XR hand-held automated analytical syringe filled with octadecyl silica sorbent. The effect of main experimental parameters of MEPS such as sample pH and ionic strength, number of aspirating/dispensing cycles, and elution solvent was studied to obtain a quantitative extraction of methylone. Oral fluid samples were spiked with methylone at different concentration levels from 50 to 400 µg L−1 and analyzed by the proposed MEPS-IMS procedure, giving …

Fourier transform infrared determination of imidacloprid in pesticide formulations

A simple method has been developed for Fourier Transform Infrared (FTIR) determination of Imidacloprid in pesticide formulations. Samples were diluted with CHCl3 and the FTIR spectra of samples and standards were obtained at a nominal resolution of 4 cm-1 from 4000 to 900 cm-1 accumulating 25 scans. Imidacloprid determination was based on the measure of either peak area from 1577 to 1567 cm-1 or peak height at 1572 cm-1, both corrected using a horizontal baseline defined at 1900 cm-1. The limits of detection achieved, of the order of 9 µg g-1, were appropriate for the determination of Imidacloprid in commercially available formulations. FTIR results were statistically comparable to those fo…