Determination of arsenite, arsenate, monomethylarsonic acid and dimethylarsinic acid in cereals by hydride generation atomic fluorescence spectrometry

Abstract A fast, sensitive and simple non-chromatographic analytical method was developed for the speciation analysis of toxic arsenic species in cereal samples, namely rice and wheat semolina. An ultrasound-assisted extraction of the toxic arsenic species was performed with 1 mol L− 1 H3PO4 and 0.1% (m/v) Triton XT-114. After extraction, As(III), As(V), dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) concentrations were determined by hydride generation atomic fluorescence spectrometry using a series of proportional equations corresponding to four different experimental reduction conditions. The detection limits of the method were 1.3, 0.9, 1.5 and 0.6 ng g− 1 for As(III), As(V)…

Validated fast procedure for trace element determination in basil powder

Abstract An inductively coupled plasma optical emission spectroscopic (ICP-OES) method has been developed and fully validated for trace element determination in basil samples. The method involves the previous sample digestion, under pressure, with a mixture of HNO 3 , HCl and H 2 O 2 inside a microwave oven, 42 elements were studied and 33 elements (Al, As, Ba, Ca, Cr, Co, Cu, Fe, Pb, Li, Mg, Mn, Mo, Ni, K, Se, Na, Sr, Tl, Ti, V, Zn, Sc, Y, La, Ce, Nd, Tb, Ho, Er, Tm, Yb, Lu) were determined quantitatively in basil leaves obtained from Morocco and Spain. The method provided recovery percentages from 89% to 113% for spiked concentrations at mg kg −1 and μg kg −1 . Accurate results were found…

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,…

Mineral Profile of Children’s Fast Food Menu Samples

Abstract Children’s fast food menus, including hamburgers served with french fries, dessert, and a soft drink, were analyzed to obtain the mineral profile of trace elements. The developed analytical methodology involved sample digestion under pressure inside a microwave oven with a mixture of HNO3 and H2O2 and inductively coupled plasma-optical emission spectrometry. The method was validated by carrying out the analysis of certified reference materials (NIST 1570a spinach leaves, NCS ZC73016 chicken, and NIST 1568a rice flour) and using recovery experiments. Repeatability was verified by analyzing replicate samples. Twenty-six elements were studied, 12 of which—aluminum, barium, calcium, co…

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).

Critical review of the atomic spectrometric analysis of arsenic in foods

The literature on the determination of arsenic in foods by atomic spectroscopy involving hydride generation, platform furnace Zeeman and inductively coupled plasma has been critically reviewed. Hydride generation has been largely displaced as a powerful tool by platform furnace Zeeman, using the STPF (stabilized temperature platform furnace) concept for the control of interferences. Inductively coupled plasma with conventional pneumatic nebulization has been little used. An alternative is to employ hydride generation-ICP with extraction of the arsenic in an organic phase. This technique permits proper control of interferences together with an increase in sensitivity. Depending on the conten…

High performance liquid chromatography—atomic fluorescence spectrometric determination of arsenic species in beer samples

Abstract A method has been developed for the direct determination of As(III), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and As(V) in beers by hydride generation—atomic fluorescence spectrometry after separation of arsenic species by high performance liquid chromatography. Compounds were separated by anion-exchange chromatography with isocratic elution using KH 2 PO 4 /K 2 HPO 4 as mobile phase with elution times of 1.67, 2.08, 6.52 and 10.72 min for As(III), DMA, MMA and As(V), respectively. Parameters affecting the hydride generation of all arsenic species were studied and the best conditions were established as a reaction coil of 150 cm, for a sample injected volume of 100 …

Direct determination by portable ED-XRF of mineral profile in cocoa powder samples

Abstract The present study has exploited the rapidity of the analysis and the multi-elemental capability of the energy dispersive X- ray fluorescence (ED-XRF) technique for the mineral profile determination in cocoa powder. A fast, cheap and environmental sustainable method without reagent consumption or toxic waste generation has been proposed. The samples can be prepared in the form of pellets of 13 mm in diameter and 2–3 mm thickness. The different internal calibrations used by ED-XRF equipment did not provide accurate results when comparing the mineral profile with the concentration obtained by Inductively Couple Plasma Optical Emission Spectroscopy (ICP-OES) after microwave assisted di…

Green methodology for quality control of elemental content of infant milk powder

Abstract A green methodology for the direct determination of elemental content in infant milk powder samples from 0 to 3 years was developed. A portable energy dispersive X-ray fluorescence (ED-XRF) tool has been used as a direct method for the quantification of five essential elements (Ca, K, Fe, Cu and Zn). For analysis pellets from 0.8 g of each sample weight were made and analyzed. Due to the high dependence of the ED-XRF signal with the sample matrix, external calibrations using cocoa powder diluted with glucose were performed. Infant milk samples were diluted with lactose and the signals were interpolated in the external calibrations. Concentrations obtained by ED-XRF were compared wi…

Determination of inorganic species of Sb and Te in cereals by hydride generation atomic fluorescence spectrometry

A non-chromatographic fast, sensitive and easy method has been developed for the determination of Sb(III), Sb(V), Te(IV) and Te(VI) in cereal samples. The procedure is based on ultrasound assisted extraction and determination by hydride generation atomic fluorescence spectrometry (HG AFS). Preliminary studies were made in order to get the best extraction efficiency using 1 mol L-1 phosphoric acid, 1 mol L-1 nitric acid, aqua regia, 1 mol L-1 sulfuric acid and 6 mol L-1 hydrochloric acid. The extraction with aquaregia showed a clear interconversion of the species during the process, being H2SO4 the best extractant with efficiencies greater than 90% from the total content of Sb and Te quantif…

On-line solvent recycling: a tool for the development of clean analytical chemistry in flow injection Fourier transform infrared spectrometry. Determination of ketoprofen

Abstract A flow injection strategy has been developed for the direct determination of ketoprofen in pharmaceuticals by Fourier transform infrared spectrometry also incorporating a distillation unit which allows the carbon tetrachloride employed to dissolve samples and standards and used as a carrier to be recovered on-line. The system developed permits a drastic reduction of reagent consumption and easy and fast sampling and cleaning of the measurement cell. For the quantification of ketoprofen in pharmaceuticals the carbonyl bands at 1712 and 1666 cm −1 were employed and the developed method provided a 3 σ limit of detection of 0.04 mg ml −1 , a dynamic range up to 10 mg ml −1 and typical …

Fast extraction methodologies for the determination of toxic arsenic in meat

Summary A nonchromatographic analytical procedure has been developed for the determination of arsenic in meat samples including the major toxic arsenic species arsenite, arsenate, monomethylarsonic acid (MMA) and dimetylarsinic acid (DMA). The method is based on the extraction of arsenic species in mild conditions, selective trivalent hydride formation and final determination by hydride generation atomic fluorescence spectroscopy (HG-AFS). Different extractant agents and two different procedures, microwave-assisted extraction (MAE) and ultrasound assisted extraction at room temperature, were evaluated for As species extraction. The method provided a limit of detection of 0.013 ng mL−1 and a…

Is lithium implicated in tobacco addiction?

IntroductionTobacco is a source of mineral elements that can affect human health in various ways, such as lithium, which is used as a psychiatric medication. Lithium salts are used as mood-stabilizing drugs and indicated in the treatment of manic-depressive psychosis.ObjectiveStudying the lithium content in tobacco over the smokers’plasma content and evaluate the potential role of lithium in tobacco addiction.MethodsA total of 18 different tobacco products (cigarettes, smokeless and water pipe tobacco) and 125 plasma samples (45 from smokers, 10 from ex-smokers and 70 from non-smokers) were collected to determinate the lithium content. Tobacco samples were digested with nitric acid and lith…

Innocampus Explora: Nuevas formas de comunicar ciencia

[EN] Innocampus Explora aims to show the students of the Burjassot-Paterna campus of the Universitat de València how the different scientific degrees are interrelated. To do this we propose activities in which students and teachers work together to cover the interdisciplinary nature of science, both in everyday and professional issues. Throughout this course the activities developed relate to new ways to communicate science. With the development of this project we contribute to a transversal quality education for all the participating students.

Inductively coupled plasma atomic emission spectrometric determination of arsenic in mussel products

A precise, accurate procedure is proposed for the determination of arsenic in mussel products by inductively coupled plasma atomic emission spectrometry. Organic matter is destroyed by dry ashing. Experimental conditions for the determination of arsenic were selected and an interference study was carried out. The methodology developed has a detection limit of 0.1 μg g−1, a relative standard deviation of 3%, and a recovery percentage of 98±2%. The accuracy of the method was checked by analysis of a certified sample of NIST oyster tissue (certified 14.0±1.2 μg g−1; found 14.1±1.1 μg g−1). The proposed procedure was used to analyze real samples of mussel products.

Simultaneous determination of hydride and non-hydride forming elements by inductively coupled plasma optical emission spectrometry

e percentagens de recuperacao entre 97 e 103%. A aplicabilidade do sistema foi demonstrada na determinacao simultânea de Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Zn, As, Bi, Sb, Se e Te em amostras certificadas para elementos tracos, NIST 1549 (leite em po desnatado), NIST 1570a (folhas de espinafre), DORM-2 (musculo de cacao) e TORT-2 (hepatopâncreas de lagosta). Os resultados obtidos foram concordantes com os teores certificados. The operating characteristics of a dual nebulization system were studied including instrumental and chemical conditions for the hydride generation and analytical figures of merit for both, hydride and non hydride forming elements. Analytical performance of the neb…

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…

A calcined clay fixed bed adsorption studies for the removal of heavy metals from aqueous solutions

Abstract A natural clay material from southern Tunisia was used as a low cost sorbent in a column-wise removal of metal pollutants. This is fundamentally important for a sustainable wastewater treatment strategy. This work has been performed within the framework of a project aiming to the valorization of natural geomaterials, from Tunisia, in several environmental applications. Column adsorption experiments were carried out for a better production of cleaner effluents and further understanding of the main mechanisms involved in the removal process, through a dynamic methodology, that would allow an industrial scale treatment. A calcined clay sample was used as an adsorbent for the removal o…

Determination of total phenolic compounds in compost by infrared spectroscopy

Abstract Middle and near infrared (MIR and NIR) were applied to determine the total phenolic compounds (TPC) content in compost samples based on models built by using partial least squares (PLS) regression. The multiplicative scatter correction, standard normal variate and first derivative were employed as spectra pretreatment, and the number of latent variable were optimized by leave-one-out cross-validation. The performance of PLS-ATR-MIR and PLS-DR-NIR models was evaluated according to root mean square error of cross validation and prediction (RMSECV and RMSEP), the coefficient of determination for prediction ( R pred 2 ) and residual predictive deviation (RPD) being obtained for this la…

Immobilization of vegetable tannins on tannery chrome shavings and their use for the removal of hexavalent chromium from contaminated water

Abstract Chestnut (C) and mimosa (M) tannins immobilized on chrome shavings (CS) as an adsorbent have been proposed to be an efficient and economical alternative in hexavalent chromium removal from aqueous solutions. The adsorption of hexavalent chromium onto chrome shavings-tannin (CS-T) adsorbents was performed using batch equilibrium technique at 25 ± 2 °C. The effect of pH is highly important especially in the case of high concentrations of hexavalent chromium. The maximum chromium uptake was obtained at pH 4. Two hours of contact time are enough to reach equilibrium. Sorption of chromium on CS-T was found to follow a pseudo-second order kinetic model (with correlation coefficients grea…

Authentication of Alicante’s Mountain cherries protected designation of origin by their mineral profile

Abstract Chemometric analysis of inductively coupled plasma optical emission spectroscopy (ICP-OES) data was employed to verify the origin of cherry samples of different areas of Spain: Aragon, Caceres, Castellon, Huesca and Alicante’s Mountain Protected Geographic Indication (PGI). The ability of multivariate analysis methods, such as discriminant analysis (DA), was used to achieve cherry classification from their mineral content. The study was performed using 22 variables (concentrations of Al, As, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Se, Sr, Ti and Te) and 23 variables (concentrations of Al, As, B, Ba, Be, Bi, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mo, Na, Ni, Pb, Se, Sr…

Near Infrared Spectroscopy Detection and Quantification of Herbal Medicines Adulterated with Sibutramine.

There is an increasing demand for herbal medicines in weight loss treatment. Some synthetic chemicals, such as sibutramine (SB), have been detected as adulterants in herbal formulations. In this study, two strategies using near infrared (NIR) spectroscopy have been developed to evaluate potential adulteration of herbal medicines with SB: a qualitative screening approach and a quantitative methodology based on multivariate calibration. Samples were composed by products commercialized as herbal medicines, as well as by laboratory adulterated samples. Spectra were obtained in the range of 14,000-4000 per cm. Using PLS-DA, a correct classification of 100% was achieved for the external validatio…

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.

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.

Innocampus Explora: Una aproximación multidisciplinar a la problemática ambiental

[ES] Presentamos las actividades del proyecto de innovación Innocampus Explora desarrollado en el campus de Burjassot-Paterna de la Universitat de València y cuyo objetivo principal es mostrar la interrelación existente entre los diferentes grados científicos y técnicos del campus. En la presente anualidad, el equipo de trabajo integrado por estudiantes y profesores de todos las facultades y escuelas del campus de Burjassot-Paterna, ha desarrollado actividades en torno a la problemática medioambiental. Una visión transversal e interdisciplinar de los problemas de los usos del plástico y de la energía nuclear que enlaza con varios de los Objetivos de Desarrollo Sostenible (ODS) dictados por …

Analysis of stratigraphical sequences at Cocina Cave (Spain) using rare earth elements geochemistry

This study investigates the stratigraphical sequence of Cocina Cave (Spain) employing and testing for the first time the capability of rare earth elements as markers of human activities in caves. Located in Dos Aguas (Valencian Community, Spain), Cocina Cave is characterized by the presence of several Holocene archaeological deposits from the final Mesolithic to the present day and is a pivotal site for understanding the socio‐ecological dynamics of the last hunter‐gatherer inhabitants of the Iberian Peninsula and the transition to pastoral and agricultural economies in the Western Mediterranean. However, the identification of strata from particular time‐periods in the cave is often difficu…

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.

Partial least squares modelization of energy dispersive X-ray fluorescence.

As a proof of concept, a green methodology has been developed for the energy dispersive X-ray fluorescence (ED-XRF) determination of calcium, potassium, iron, magnesium, aluminum, chromium, strontium, phosphorus and nickel in the peel of untreated kaki fruit (Diospyros kaki. L) samples. ED-XRF spectra of fifty-six kakis purchased in the local area of LLombay (Valencia) were obtained directly from samples without any previous treatment and without sample damage just after cleaning the fruit with distilled water. Inductively Couple Plasma Optical Emission Spectrometry (ICP-OES) was used as a reference method to determine the mineral elements after microwave assisted acid digestion. XRF spectr…

Kinetic, isotherm and thermodynamic studies of the adsorption of methylene blue dye onto agro-based cellulosic materials

AbstractThe purpose of this work is to establish the optimal experimental conditions for the removal of methylene blue (MB-as model basic dye) from aqueous solution by adsorption onto four agro-based materials, namely, cedar sawdust, pine sawdust, wheat straw, and Provence cane Arundo donax. Results show that an increase in acidity or ionic strength of the medium has generally a negative effect on the discoloration yield. From the data of pH effect, there is no need to change the initial pH of the MB solution to be treated. Equilibrium was reached after 20−30 min of agitation when cedar sawdust, pine sawdust, and Provence cane are used as adsorbents. However, in the case of wheat straw, an …

Chemometric determination of arsenic and lead in untreated powdered red paprika by diffuse reflectance near-infrared spectroscopy.

It has been evaluated the potential of near-infrared (NIR) diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) as a way for non-destructive measurement of trace elements at microg kg(-1) level in foods, with neither physical nor chemical pre-treatment. Predictive models were developed using partial least-square (PLS) multivariate approaches based on first-order derivative spectra. A critical comparison of two spectral pre-treatments, multiplicative signal correction (MSC) and standard normal variate (SNV) was also made. The PLS models built after using SNV provided the best prediction results for the determination of arsenic and lead in powdered red paprika samples. Relativ…

Cereals and pulses

Mineral profiles of legumes and fruits through partial least squares energy dispersive X-ray fluorescence

Abstarct Energy dispersive X-ray fluorescence (ED-XRF) has been employed for the determination of mineral elements in 15 varieties of legumes and 14 cherry samples. ED-XRF signals directly obtained from pulverized samples were modelized by partial least squares (PLS) using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) of a selected number of samples, after microwave assisted acid digestion, as reference data. Models were built to predict the concentration of Al, Ca, Cu, Fe, K, Mg, P, Sr and Zn. Average concentrations predicted were 6, 930, 7, 40, 6400, 990, 2100, 4 and 15 μg g−1 for Al, Ca, Cu, Fe, K, Mg, P, Sr and Zn, respectively with relative errors from 7 till 26%. …

Fast determination of fish mineral profile. Application to Vietnamese panga fish

A methodology, based on inductively coupled plasma optical emission spectrometry after microwave-assisted digestion with HNO3/H2O2, was developed to determine the mineral profile of panga fish samples imported from Vietnam. A total of 42 essential and toxic elements were studied in seven samples taken from the local market. Preliminary studies were focused on selecting the best wavelength and the required dilution of samples in order to provide the highest sensitivity to maximize the number of analytes to be determined without spectral or matrix interferences. Adequate accuracy was assured by the analysis of certified reference material TORT-2. Mercury was also determined by a direct method…

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.

Non-chromatographic speciation of mercury in mushrooms

A fast, sensitive and cheap procedure has been developed for the determination of inorganic mercury (i-Hg) and organic mercury (o-Hg) in mushroom samples. The procedure is based on the use of cold vapour atomic fluorescence spectrometry (CV-AFS). The method involves the extraction of total mercury (t-Hg) with diluted HCl, followed by measurements of the corresponding Hg vapour under two different conditions: (i) directly to determine i-Hg, and (ii) after oxidation with a mixture KBr/KBrO3 to determine t-Hg. o-Hg was estimated from the difference between t-Hg and i-Hg. Previous studies were focused on the assessment of different reagents for mercury extraction and breakdown of organomercury …

Prediction of organic carbon and total nitrogen contents in organic wastes and their composts by Infrared spectroscopy and partial least square regression

Middle and near infrared (MIR and NIR) were employed to determine organic carbon (OC) and total nitrogen (TN) in different soil organic amendments including wastes, composts and mixtures of composts and organic wastes. Prediction models based on partial least squares (PLS) regression from the spectra of untreated samples were built. Different spectra preprocessing strategies were adopted and the best number of latent variable was evaluated using leave-one-out cross-validation. Attenuated total reflectance (PLS-ATR-MIR) and diffuse reflectance (PLS-DR-NIR) models were built and evaluated from root mean square error of cross validation and prediction (RMSECV and RMSEP), coefficients of determ…

Smartphone determination of fat in cured meat products

Abstract A method has been developed to determine the fat content in different cold meat products by image processing using the camera of a mobile phone. Salchichon , chorizo , salami and cured ham pictures were taken with a Meizu M2 Mini mobile phone camera under fixed lighting conditions of the light emitting diode flash of the mobile phone. Images were treated with Matlab to obtain the mean pixels of average red, green and blue camera values colours (RGB) of the pixels and different data pretreatments were taken into account to correlate colour parameters with fat content values determined in a series of commercially available samples by the Soxhlet method. RGB values were used as input …

Total content of As, Sb, Se, Te and Bi in Spanish vegetables, cereals and pulses and estimation of the contribution of these foods to the Mediterranean daily intake of trace elements

Abstract As, Sb, Se, Te and Bi were quantified in vegetables, pulses and cereals, in order to increase the available information on the presence of these elements in the Mediterranean daily intake. Samples were dry ashed and the ashes dissolved with diluted HCl. Hydride generation atomic fluorescence spectrometry was used for quantification. Limits of detection (LOD) ranged from 0.2 to 1.7 ng g−1 and the accuracy was assessed by the analysis of three certified reference materials, Rice Flour (NIST 1568a), Tomato Leaves (NIST 1573) and Cabbage (IAEA 359). Good concordance between results found and certified values were always observed. As, Sb, Se, Te and Bi levels varied in samples analysed …