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

Abstract

Owing 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 exhibit cytotoxicity, photoallergy, mutagenicity, and carcinogenicity activities. To monitor for contamination of QdNOS in abalone and assess dietary exposure, a simple and reliable analytical method for the detection of QdNOs and their major metabolites was developed. 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 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 ranged from 0.16 to 2.1μg kg-1 for QdNOs and their major metabolites. These results indicate that the LC-MS/MS method developed 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 the often-ignored exposure pathway of QdNOs. © 2019 Society of Chemical Industry.