Search results for "Trap"
showing 10 items of 2144 documents
Mycotoxins in cereals and pulses harvested in Latvia by nanoLC-Orbitrap MS
2021
Twenty-seven mycotoxins in unprocessed cereals (n = 110) and pulses (n = 23) harvested in Latvia were analysed by nanoflow liquid chromatography combined with Orbitrap high-resolution mass spectrometry. One or more mycotoxins were found in 99% of the cereals and 78% of the pulses. Deoxynivalenol, zearalenone and T-2 and HT-2 toxins were prevalent in 9 to 86% of the cereals, mostly below their maximum levels as set by the European regulations. Non-regulated type A and B trichothecenes were prevalent in 5 to 87% of the cereals, at concentrations of 0.27–83 µg kg−1 and 1.7–4,781 µg kg−1, respectively. Quantification of emerging mycotoxins was also provided. Enniatins were detected in 94% of th…
Gas chromatography and mass spectroscopy techniques for the detection of chemical contaminants and residues in foods
2017
Gas chromatography-mass spectrometry (GC-MS) is a cornerstone for qualitative and quantitative analysis of food contaminants and residues. It is fast and sensitive, provides a high peak capacity, and allows determination of thermally stable and volatile compounds. Recent research has resulted in better chromatographic columns and methods for sample preparation that enable a significant expansion of the application range of GC-MS, profiling strategies for sample characterization being identified as important future drivers. Newer detection/separation solutions, such as fast chromatography, comprehensive two-dimensional GC (GC × GC), triple quadrupole MS, time-of-flight MS or orbitrap, atmosp…
Ultra-high-pressure liquid chromatography tandem mass spectrometry method for the determination of 9 organophosphate flame retardants in water samples
2016
Few methods are available for comprehensive organophosphate flame retardants (PFRs) detection in water and wastewater. Gas chromatography has been employed previously, but this approach is less selective, not amenable for use with deuterated standards and can suffer unfavorable fragmentation. Ultra-high-pressure liquid chromatography tandem mass spectrometry (UHPLC-QqQ-MS/MS) has become the most promising platform, already applied successfully for analysis of selected PFRs in some environmental matrices like water and wastewater. However, the presence of some interferences from the dissolvent, the equipment and the used materials should be taken into account. The procedure involves: The fir…
Comparison of liquid chromatography using triple quadrupole and quadrupole ion trap mass analyzers to determine pesticide residues in oranges.
2005
Liquid chromatography-triple quadrupole/mass spectrometry (LC-TQ/MS) and liquid chromatography-quadrupole ion trap/mass spectrometry (LC-QIT/MS) for determining bupirimate, hexaflumuron, tebufenpyrad, buprofezin, pyriproxyfen, and fluvalinate in fruits have been compared. The differences in the mass spectra obtained by triple and ion trap quadrupoles are discussed, showing how both of them provide interesting features. The evaluation of the two instruments was carried out by ethyl acetate extraction of oranges spiked with the studied pesticides at LOQ and 10 times the LOQ. Results obtained by LC-TQ/MS correlated well with those obtained by LC-QIT/MS. Recoveries were 70-94% by LC-TQ/MS and 7…
Metabolites of the aquatic pollutant diclofenac in fish bile.
2010
The uptake and metabolism of anti-inflammatory drug diclofenac (DCF) was studied by exposing rainbow trout (Oncorhynchus mykiss) to DCF intraperitoneally, and via water at concentration of 1.7 μg L(-1). The bile was collected and the formed metabolites were identified. The identification was based on the exact mass determinations by a time-of-flight mass analyzer and on the studies of fragments and fragmentation patterns of precursor ions by an ion trap mass analyzer. The main metabolites found were acyl glucuronides of hydroxylated DCFs. In addition, one ether glucuronide of hydroxylated DCF was found. Also, unmetabolized DCF was detected in the bile. The total bioconcentration factors (BC…
Retrospective screening of pesticide metabolites in ambient air using liquid chromatography coupled to high-resolution mass spectrometry
2015
A new methodology for the retrospective screening of pesticide metabolites in ambient air was developed, using liquid chromatography coupled to Orbitrap high-resolution mass spectrometry (UHPLC-HRMS), including two systematic workflows (i) post-run target screening (suspect screening) and (ii) non-target screening. An accurate-mass database was built and used for the post-run screening analysis. The database contained 240 pesticide metabolites found in different matrixes such as air, soil, water, plants, animals and humans. For non-target analysis, a "fragmentation-degradation" relationship strategy was selected. The proposed methodology was applied to 31 air samples (PM10) collected in the…
Capabilities of different liquid chromatography tandem mass spectrometry systems in determining pesticide residues in food
2007
Abstract Three different liquid chromatography–mass spectrometry (LC–MS) instruments equipped with triple quadrupole (QqQ), quadrupole ion trap (QIT) and quadrupole-time-of-flight (QqTOF), suitable to carry out tandem mass spectrometry, were examined to determine pesticide residues in food. Twelve pesticides (acrinathrin, bupirimate, buprofezin, cyproconazole, λ-cyhalothrin, fluvalinate, hexaflumuron, kresoxim-methyl, propanil, pyrifenox, pyriproxyfen and tebufenpyrad) and six matrices (oranges, strawberries, cherries, peaches, apricots and pears) were taken as model. The comparison was focused on two aspects: the quantitative, covering sensitivity, precision and accuracy as well as the qua…
Target analysis of primary aromatic amines combined with a comprehensive screening of migrating substances in kitchen utensils by liquid chromatograp…
2015
An analytical strategy including both the quantitative target analysis of 8 regulated primary aromatic amines (PAAs), as well as a comprehensive post-run target screening of 77 migrating substances, was developed for nylon utensils, using liquid chromatography-orbitrap-high resolution mass spectrometry (LC-HRMS) operating in full scan mode. The accurate mass data were acquired with a resolving power of 50,000 FWHM (scan speed, 2 Hz), and by alternating two acquisition events, ESI+ with and without fragmentation. The target method was validated after statistical optimization of the main ionization and fragmentation parameters. The quantitative method presented appropriate performance to be u…
Quick determination of Glyphosate and AMPA at sub µg/L in drinking water by direct injection into LC-MS/MS
2021
Abstract A sensitive, simple and quick method for the determination of glyphosate (Gly) and its degradation product, Aminomethyl phosphonic acid (AMPA), in water through ion chromatography coupled to quadrupole-linear ion trap mass spectrometry has been developed. Sample treatment was based on direct injection and acquisition was implemented in both MS2 and MS3 modes. The LoQs of the method were 0.03 µ/L for both Gly-and AMPA. The recoveries were between 91 and 118% and RSD was lower than 15%. The developed methodology was applied on 436 water samples.
Electron paramagnetic resonance (EPR) spin trapping of biological nitric oxide
2007
Nitric oxide (NO) is a free radical species with multiple physiological functions. Because of low concentrations and short half-life of NO, its direct measurement in living tissues remains a difficult task. Electron paramagnetic resonance (EPR) spin trapping is probably one of the best suitable platforms for development of new methods for quantification of biological NO. The most reliable EPR-based approaches developed so far are based on the reaction of NO with various iron complexes, both intrinsic and exogenously applied. This review is focused on the current state and perspectives of EPR spin trapping for experimental and clinical NO biology.