Nontargeted screening strategy of chemical residues in animal-derived foods based on endogenous metabolite global annotation and interquartile range filtering by ultrahigh-performance liquid chromatography-high-resolution mass spectrometry.

Endogenous components and other experimental background information can interfere with the efficiency of nontargeted screening for unknown chemical residues in complex food matrices. In this study, a new nontargeted screening strategy of chemical residues in animal-derived foods was developed based on endogenous metabolite global annotation and interquartile range (IQR) filtering by ultrahigh-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS). First, endogenous metabolite global annotation was employed to eliminate the majority of endogenous components and their related ion peaks in food from the UHPLC-HRMS data. Second, IQR filtering was evaluated across multiple intercept values under different sample sizes and spiking concentrations based on 72 standards of chemical residues. The evaluation results indicated that chemical residues could be rapidly found after background interference was effectively removed when the sum of the third quartile and 20 times the interquartile range was used as intercept values. By integrating endogenous metabolite global annotation information with IQR filtering, this strategy achieved a total background interference filtering performance of >95 %. Finally, this strategy was applied to screen 13 meat samples. Suspected chemical residues in meat samples were successfully found out and identified by endogenous metabolite global annotation and IQR filtering, and the overall capability for filtering background interference reached 93.1 %. The strategy effectively improved the efficiency of nontargeted screening for unknown chemical residues in animal-derived foods, which can provide a powerful tool for routine risk assessment of food safety.