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.
A simple, rapid, and efficient liquid chromatography tandem mass spectrometry (LC–MS/MS) method, operated in electrospray ionization and quadrupole linear ion trap modes, has been developed for the identification and structural characterization of aflatoxins in peanuts and its derivative products or bean sauce. Samples (5 g) were extracted with acetonitrile/water/formic acid (79:20:1, v/v). After centrifugation and dilution, the extracts were separated on a C18 analytical column by gradient elution (acetonitrile/0.2% formic acid) and analyzed by UPLC–MS/MS. External calibration was used for qualification. The developed multiple reaction monitoring–information-dependent acquisition–enhanced product ion method enabled quantification and confirmation of the analytes in a single run. Enhanced product ion mode was used for qualitative analysis, while multiple reaction monitoring mode was used for quantitative analysis. An in-house library was constructed for identification. Calibration curves showed good linearity with correlation coefficients (r) higher than 0.994. Limits of detection were determined to be below 0.26 µg kg−1 for most analytes. The recoveries for those substances were in the acceptable range of 80.2%–119.1%. A new LC–MS3 method was established for further confirmation. One pickled pepper peanut was found to contain aflatoxins B1, B2, and G1 with contents of 90.93, 26.64, and 1.92 µg kg−1, respectively.
Background: A simple, rapid, and e cient liquid chromatography tandem mass spectrometry (LC-MS/MS) method, operated in electrospray ionization (ESI) and quadrupole linear ion trap modes, has been developed for the identi cation and structural characterization of zearalenone (ZEN) in corn oil. Methods: Samples (5 g) were extracted with acetonitrile/water (80:20, v/v). After centrifugation and dilution, the extracts were separated on a C18 analytical column by gradient elution (acetonitrile/water) and analyzed by UPLC-MS/MS. Enhanced product ion mode was used for qualitative analysis, while multiple reaction monitoring mode was used for quantitative analysis.Results: Calibration curve showed good linearity with correlation coe cients (r) higher than 0.995. Limit of detection was determined to be below 0.20 μg kg -1 for ZEN. The recovery for ZEN was in the acceptable range of 86.6% to 97.2%. 82.4 % of the samples were found to contain ZEN among the 51 samples.
Conclusion:The sample pretreatment and LC-MS methods developed in this research, from a convenience and analysis time perspective, are simple, e cient, cheaper, and less time-consuming than existing methods.
Background: A simple, rapid, and efficient liquid chromatography tandem mass spectrometry (LC–MS/MS) method, operated in electrospray ionization (ESI) and quadrupole linear ion trap modes, has been developed for the identification and structural characterization of zearalenone (ZEN) in corn oil. Methods: Samples (5 g) were extracted with acetonitrile/water (80:20, v/v). After centrifugation and dilution, the extracts were separated on a C18 analytical column by gradient elution (acetonitrile/water) and analyzed by UPLC–MS/MS. Enhanced product ion mode was used for qualitative analysis, while multiple reaction monitoring mode was used for quantitative analysis. Results: Calibration curve showed good linearity with correlation coefficients (r) higher than 0.995. Limit of detection was determined to be below 0.20 μg kg-1 for ZEN. The recovery for ZEN was in the acceptable range of 86.6% to 97.2%. 82.4 % of the samples were found to contain ZEN among the 51 samples.Conclusion: The sample pretreatment and LC–MS methods developed in this research, from a convenience and analysis time perspective, are simple, efficient, cheaper, and less time-consuming than existing methods.
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