Search results for "Spectrometry"
showing 10 items of 3206 documents
Tuning the selectivity of molecularly imprinted polymer extraction of arylcyclohexylamines: From class-selective to specific
2020
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…
Determination of trichothecenes and zearalenones in grain cereal, flour and bread by liquid chromatography tandem mass spectrometry
2012
Although analytical methods have been already reported for legislated mycotoxins as trichothecenes and zearalenone (ZON) separately, we describe the optimization of a simple and rapid multimycotoxin method for the determination of a total of 12 mycotoxins simultaneously, nine trichothecenes (NIV, DON, FUS-X, DAS, 15-AcDON, 3-AcDON, NEO, HT-2, T-2 T2), and zearalenone and its metabolites (ZON, a-ZOL, b-ZOL), of different origin (wheat, oat, barley and spelt) and in three different products where these substance can be present (grain, flour and bread) reach the food chain and cause toxic effect either in humans or animals. The extraction procedure was based on a mixture of acetonitrile/water …
Extraction and Sample Preparation
2015
As everyone knows, the role played by extraction and sample preparation in the analytical sciences cannot be overemphasized. Despite tremendous advances in chromatography, detection, and other aspects of analysis, extraction and sample preparation remain a preanalysis ritual of critical importance. It has been estimated that around 50% to 70% possibly even more of the time and effort that goes into an analytical process comprises extraction and sample preparation. Sample preparation procedure can vary in the degree of selectivity, speed, and convenience, depending on the approach and conditions used, as well as on the geometric configurations of the extraction phase and conditions. Proper d…
Synergistic combination of polyamide-coated paper-based sorptive phase for the extraction of antibiotics in saliva.
2021
Abstract The development of analytical methods that allow the simultaneous determination of a wide range of analytes with different properties is one of the focuses of attention in Analytical Chemistry. This work describes a proof-of-concept of the synergistic extraction of a planar paper-based sorptive phase modified with a polyamide such as nylon. This as-prepared sorptive phase enables the extraction of six penicillin-derived antibiotics of different polarity from human saliva samples in the same analysis, since the analytes either interact with the paper or with the nylon. The synthesis of the sorptive phase is simple as it only requires dipping the paper into an organic solution of the…
Analysis of four parabens and bisphenols A, F, S in urine, using dilute and shoot and liquid chromatography coupled to mass spectrometry
2018
Abstract A new strategy for the analysis of 4 parabens (methylparaben, ethyl paraben, propyl paraben and butyl paraben) and 3 bisphenols (A, F and S) in human urine has been developed. Dilute and shoot and liquid chromatography coupled to mass spectrometry (LC-MS/MS) determination was employed. Procedural matched calibration, certified materials and spiked samples were used for validation. The obtained recoveries varied between 85 and 104% with a precision lower than 20% for all analytes. The LOQ was 0.20 ng mL for all analytes. Negative atmospheric pressure chemical ionization in the selected reaction monitoring mode was used for MS detection. The proposed method was successfully applied f…
Diffusion technique for the generation of gaseous halogen standards
2009
Abstract Halogens are known to play an important role in the tropospheric ozone-depletion chemistry and are of special interest because of their influence on the atmospheric oxidation capacity. In this paper, we investigate the application of a capillary diffusion technique for the generation of gaseous halogen standards like Br 2 , IBr, ICl and I 2 . The influence of capillary dimension (i.e. length and inner diameter), ambient pressure and headspace volume of the diffusion vessel on the test gas output has been evaluated. The experimental output rates are determined from the mass loss of the analyte vessel on a regular schedule and compared with their respective theoretical predictions. W…
Amphetamine-type stimulants analysis in oral fluid based on molecularly imprinting extraction
2018
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 …
Automated Photo-Induced Fluorescence Determination of Flumetsulam
2009
The present article deals with a new procedure for determination of the herbicide flumetsulam. The fluorimetric procedure is performed on the basis of photo-increased fluorimetric emission of the pesticide solution and by means of a multicommutation continuous-flow assembly. The alkaline solution containing the analyte is irradiated online and then directly forced through the fluorimeter flow cell. The analysis of different samples is completely automated, as the analyte separation was performed online by including a separation cartridge in the manifold. When dealing with solid samples (such as soil samples), the automation was completed by adding to the manifold the corresponding device fo…
Analytical capabilities of high performance liquid chromatography – Atmospheric pressure photoionization – Orbitrap mass spectrometry (HPLC-APPI-Orbi…
2015
A new analytical method was established and validated for the analysis of 27 brominated flame retardants (BFRs), including so called "emerging" and "novel" BFRs (EBFRs and NBFRs) in fish samples. High performance liquid chromatography (HPLC) coupled to Orbitrap mass spectrometry (Orbitrap-MS) employing atmospheric pressure photoionization (APPI) interface operated in negative mode was used for the identification/quantitation of contaminants. HPLC-Orbitrap-MS analysis provided a fast separation of selected analytes within 14 min, thus demonstrating a high throughput processing of samples. The developed methodology was tested by intralaboratory validation in terms of recovery, repeatability, …
In-tube solid phase microextraction coupled to miniaturized liquid chromatography for both, noble metal nanoparticle assessment and sensitive plasmon…
2021
Abstract Colorimetric localized surface plasmon resonance (LSPR) as analytical response is applied for a wide number of chemical sensors and biosensors. However, the dependence of different factors, such as size distribution of nanoparticles (NPs), shape, dielectric environment, inter-particle distance and matrix, among others, can provide non-reliable results by UV–vis spectrometry in complex matrices if NP assessment is not carried out, particularly at low levels of analyte concentrations. Miniaturized liquid chromatography, capillary (CapLC) and nano (NanoLC), coupled on line with in-tube solid phase microextraction (IT-SPME) is proposed for the first time for both, controlling suitabili…