Analysis of ethoxyquin and its oxidation products in swine tissues by gas chromatography-tandem mass spectrometry for evaluating the feed-to-animal tissue transfer of ethoxyquin and its metabolites

• Main Authors: Chi Zhang, Xiangrong Gai, Ying Tian, Jiayi Wang, Dongting He, Wenjun Yang, Liying Zhang, Yiqiang Chen
• Format: Article
• Language: English
• Published: BMC 2021-01-01
• Series: Journal of Animal Science and Biotechnology
• Subjects: Ethoxyquin; Ethoxyquin dimer; Ethoxyquin quinone imine; Gas chromatography-tandem mass spectrometry; Safety evaluation; Swine tissues
• Online Access: https://doi.org/10.1186/s40104-020-00529-z

Abstract Background Ethoxyquin (EQ) is a common antioxidant which is widely used in animal feed. But the supplement of EQ in animal feed may lead to the residues of EQ and its major oxidation products: ethoxyquin quinone imine (EQI) and ethoxyquin dimer (EQDM) in animal tissue. Thus, it would pose potential health hazards to consumers. However, the method for the simultaneous determination of EQ, EQI and EQDM in animal tissues is currently not available, and the accumulation extend of these chemicals in animal tissues after EQ administration remains to be evaluated. Results A gas chromatography-tandem mass spectrometry method was successfully developed for the simultaneous determination of EQ, EQI and EQDM in swine tissues. The quantitative limits of EQ, EQI and EQDM can achieve to 0.5, 5.0 and 5.0 μg/kg in swine tissues, respectively. The spiked-recovery ratios of the three analytes (5–2000 μg/kg) were in the range of 64.7%–100.7% with relative standard deviations below 11.6%. Moreover, the utilization of this method for the analysis of actual swine tissue samples revealed that the application of commercial EQ additive in swine diet would produce the residues of all the three chemicals (EQ, EQI and EQDM) in fat, kidney, liver and muscle. Conclusions The assay accuracy and precision of this GC-MS/MS method can meet the requirement of quantitative analysis. Meanwhile, the safety of EQ as a feed additive should be seriously considered with regard to food safety concerns since the oxidation product of EQ may have potential carcinogenicity.