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

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.

Microfluidic Electrochemistry Meets Trapped Ion Mobility Spectrometry and High-Resolution Mass Spectrometry—In Situ Generation, Separation, and Detection of Isomeric Conjugates of Paracetamol and Ethoxyquin

“…The reason for this was the lack of data on the safety of EQ and its transformation products for the consumer. In contrast to APAP, EQ and its metabolism have not yet been entirely elucidated, which is why it continues to be suspended as a feed additive, and are already in the focus of investigation by different research groups. − However, not only the metabolites but also the oxidation products, which can be formed during transport and storage times, can be dangerous for humans and the environment. − Among the most controversial transformation products of EQ are EQ-dimer (EQDM), which can accumulate in fish, and EQ quinone imine (EQI), which is highly reactive. Merel et al presented all known transformation products of EQ in 2019 .…”