Quantification and Confirmation of Zearalenone Using a LC-MS/MS QTRAP System in Multiple Reaction Monitoring and Enhanced Product Ion Scan Modes

Author(s):  
Shencong Lv ◽  
Xiaoqiong Wu ◽  
Jian Guan ◽  
Yong Yan ◽  
Miaohua Ge ◽  
...  
Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2496 ◽  
Author(s):  
Ying Zhou ◽  
Jian Guan ◽  
Weiwei Gao ◽  
Shencong Lv ◽  
Miaohua Ge

In this research, fifteen carbamate pesticide residues were systematically analyzed by ultra-high performance liquid chromatography–quadrupole-linear ion trap mass spectrometry on a QTRAP 5500 system in both multiple reaction monitoring (MRM) and enhanced product ion (EPI) scan modes. The carbamate pesticide residues were extracted from a variety of samples by QuEChERS method and separated by a popular reverse phase column (Waters BEH C18). Except for the current conformation criteria including selected ion pairs, retention time and relative intensities from MRM scan mode, the presence of carbamate pesticide residues in diverse samples, especially some doubtful cases, could also be confirmed by the matching of carbamate pesticide spectra via EPI scan mode. Moreover, the fragmentation routes of fifteen carbamates were firstly explained based on the mass spectra obtained by a QTRAP system; the characteristic fragment ion from a neutral loss of CH3NCO (−57 Da) could be observed. The limits of detection and quantification for fifteen carbamates were 0.2–2.0 μg kg−1 and 0.5–5.0 μg kg−1, respectively. For the intra- (n = 3) and inter-day (n = 15) precisions, the recoveries of fifteen carbamates from spiked samples ranged from 88.1% to 118.4%, and the coefficients of variation (CVs) were all below 10%. The method was applied to pesticide residues detection in fruit, vegetable and green tea samples taken from local markets, in which carbamates were extensively detected but all below the standard of maximum residue limit.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 362-363
Author(s):  
Daniil Khvostov ◽  
Natalya Vostrikova ◽  
Irina M Chernukha

Abstract Functional, particularly personalized meat-based foods are of more in demand by a consumer today. Functional additives, such as plant components and animal proteins from bovine or porcine tissues have been successfully used. With many ingredients added to foods, it is important to provide quality and composition monitoring to confirm the products’ authenticity, to identify undeclared or rarely used types of raw meat in product formulations. For example, if animal heart tissue is a component of a product formulation or if aorta tissue presents in a product due to improper trimming. Different methods are used to identify raw materials, including new approaches in proteomics and peptidomics that are considered the most effective modern methods nowadays. The purpose of the study is meat product composition analysis and special biomarker peptide identification to confirm the presence of heart and aorta tissue in a finished meat product. Over 20 amino acid sequences were checked based on earlier obtained data. Those amino acid sequences were analyzed with a high-performance liquid chromatography with mass spectrometric detection as described. The MS settings were selected using the Skyline. Signal-to-Noise ratio (S/N) over 10 units were used to choose the best peptide candidates. Seven peptides were found in porcine hearts. The best candidate was peptide VNVDEVGGEALGR (S/N - 73.10±5.3) from β-Hemoglobin. Two marker peptides from serum albumin were selected for pork aorta: TVLGNFAAFVQK (S/N 53.51±2.4) and EVTEFAK (S/N 31.69±4.1). These biomarkers showed the best detection and specificity. The multiply reaction monitoring method made it possible to identify the most/best specific peptides—biomarkers that could confirm the heart and/or aorta in meat products. The method can be used for comparative research or identification of best peptides that are specific to any type of animal tissue. The work was supported by the Russian Science Foundation, project no. 16-16- 10073.


2014 ◽  
Vol 60 (2) ◽  
pp. 353-360 ◽  
Author(s):  
Lynn Carr ◽  
Anne-Laure Gagez ◽  
Marie Essig ◽  
François-Ludovic Sauvage ◽  
Pierre Marquet ◽  
...  

Abstract BACKGROUND Blood concentrations of the calcineurin inhibitors (CNIs) cyclosporine and tacrolimus are currently measured to monitor immunosuppression in transplant patients. The measurement of calcineurin (CN) phosphatase activity has been proposed as a complementary pharmacodynamic approach. However, determining CN activity with current methods is not practical. We developed a new method amenable to routine use. METHODS Using liquid chromatography–multiple reaction monitoring mass spectrometry (LC-MRM-MS), we quantified CN activity by measuring the dephosphorylation of a synthetic phosphopeptide substrate. A stable isotope analog of the product peptide served as internal standard, and a novel inhibitor cocktail minimized dephosphorylation by other major serine/threonine phosphatases. The assay was used to determine CN activity in peripheral blood mononuclear cells (PBMCs) isolated from 20 CNI-treated kidney transplant patients and 9 healthy volunteers. RESULTS Linearity was observed from 0.16 to 2.5 μmol/L of product peptide, with accuracy in the 15% tolerance range. Intraassay and interassay recoveries were 100.6 (9.6) and 100 (7.5), respectively. Michaelis–Menten kinetics for purified CN were Km = 10.7 (1.6) μmol/L, Vmax = 2.8 (0.3) μmol/min · mg, and for Jurkat lysate, Km = 182.2 (118.0) μmol/L, Vmax = 0.013 (0.006) μmol/min · mg. PBMC CN activity was successfully measured in a single tube with an inhibitor cocktail. CONCLUSIONS Because LC-MRM-MS is commonly used in routine clinical dosage of drugs, this CN activity assay could be applied, with parallel blood drug concentration monitoring, to a large panel of patients to reevaluate the validity of PBMC CN activity monitoring.


2013 ◽  
Vol 12 (12) ◽  
pp. 5996-6003 ◽  
Author(s):  
De Lin ◽  
William E. Alborn ◽  
Robbert J. C. Slebos ◽  
Daniel C. Liebler

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