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Tracing major metabolites of quinoxaline-1,4-dioxides in abalone with high performance liquid chromatography tandem positive mode electrospray ionization mass spectrometry.

BACKGROUND
Due to the comprehensive application of quinoxaline-1,4-dioxides (QdNOs) in aquaculture, QdNOs and metabolites are often detected in marine food, including abalone. QdNOs are reported to exhibitcytotoxicity, photoallergy, mutagenicity and carcinogenicity activities. To monitor forcontamination of QdNOS in abalone and assess dietary exposure, a simple and reliable analytical method for the detection of QdNOs as well as their major metabolites was developed RESULTS: This work is the first to present a simple and fast pretreatment procedure coupled with high performance liquid chromatography tandem positive mode electrospray ionization mass spectrometry (LC-MS/MS) for tracing of major metabolites of quinoxaline-1,4-dioxides (QdNOs) in abalone. Extraction steps were simplified by the use of methanol and ethyl acetate containing 0.1% formic acid instead of more complicated acidolysis and enzymolysis pretreatment procedures. High-sensitive characters were obtained with limits of detection (LODs) ranged from 0.16 to 2.1 μg kg-1 for QdNOs and their major metabolites.


CONCLUSION
These results indicated that the developed LC-MS/MS method could be applied for QdNOs and major metabolites detection in actual samples. Considering the large production and consumption of abalone in Shandong Province, China, this work will also contribute to the further understanding of often ignored exposure pathway of QdNOs. This article is protected by copyright. All rights reserved.