气相色谱-三重四极杆质谱动态多反应监测模式测定枸杞干果中118种农药残留
摘要
<p id=C2>Wolfberry fruit is very popular among consumers because it is rich in nutrients. However, it is vulnerable to diseases caused by insect pest feeding and microbial pathogen infection. Pesticide application is the main approach for controlling wolfberry disease; however, various concerns have been raised regarding chemical residues in foodstuffs and consequent environmental contamination. Matrix interference is a significant challenge in trace analysis. Chromatography, coupled with MS techniques with high sensitivity and selectivity, proved to be a powerful tool for the detection of multi-pesticide residues in complex matrices. The traditional MRM mode has been gradually replaced by the dynamic MRM (dMRM) mode, which could dynamically allocate the retention time window of each target pesticide, significantly adjust the loading cycle time of multiple compounds, and improve the analysis efficiency. The QuEChERS pretreatment method, based on dispersive solid-phase extraction, has been widely used in the detection of pesticide residues in food because it is simple and rapid. In this study, a robust and high-throughput method was established for the simultaneous determination of 118 pesticide residues in wolfberry using the modified QuEChERS method, combined with gas chromatography-triple quadrupole mass spectrometry in dMRM mode. The optimal pretreatment method was determined by comparing the recovery rates obtained with different volumes of added water (5, 10, 15, and 20 mL), different extraction solvents (acetone, <italic>n</italic>-hexane, acetonitrile, and acetonitrile containing 0.1% formic acid), different extraction temperatures (normal temperature, -18 ℃ for 10 min and 20 min), water absorbent (anhydrous magnesium sulfate), and purification with primary secondary amine (PSA) and octadecylsilane (C<sub>18</sub>). The results showed that 5 g samples were rehydrated with 10 mL ultrapure water, extracted with 10 mL acetonitrile, frozen at -18 ℃ for 10 min, pa