Characterization of quinoxaline-1,4-dioxides and major metabolites accumulation from marine ranching to sea cucumber

Abstract

In this work, quinoxaline-1,4-dioxides (QdNOs) exposure in sea cucumber from marine ranching to table have been identified and quantified. A reliable LC-MS/MS protocol for qualitative and quantitative analysis of QdNOs and their major metabolites in feeds and sea cucumbers was established and validated. Mequindox (MEQ) and quinocetone (QCT) contaminated in commercial sea cucumber feeds were evaluated with positive rate around 70% and 10%, respectively. In sea cucumbers samples, major metabolites of QdNOs, 3-methyl-quinoxaline-2-carboxylic (MQCA) and 4-desoxy-MEQ (4-DMEQ) as well as MEQ were also evaluated with positive rate at 36%, 16%, and 66%, respectively. The results indicated that MQCA and 4-DMEQ are the major metabolites of MEQ in sea cucumber, and QdNOs and metabolites in sea cucumber samples might be derived from feeds in marine ranching. This work illustrates the exposure of QdNOs from marine feed to sea cucumbers, and the results will contribute for QdNOs metabolism investigation and further control in marine food.