Extraction and detection of a new arsine sulfide containing arsenosugar in molluscs by IC-ICP-MS and IC-ESI-MS/MS

Abstract

Using IC-ICP-MS and IC-ESI-MS/MS, an unknown arsenical compound in molluscs has been identified as a new arsine sulfide containing analog of a known arsenosugar and is referred to as As(498). This species has been observed in four separate shellfish species following a mild methanol–water extraction. As(498) is unstable, especially in acid, and converts to the arsine oxide containing arsenosugar As(482) over time. Chromatographic retention of As(498) was observed on an anion exchanger ION-120 column but the species did not elute as a well defined peak from a PRP-X100. Mass spectrometric analysis of As(498) at pH 9.0 produced an [M–H]⁻ species at a mass to charge of 497 in the negative-ion mode. A synthetic standard of As(498) was made by bubbling hydrogen sulfide into a stock solution of arsenosugar As(482). The retention time and ESI-MS/MS data were identical for the synthetic standard of As(498) and the unknown arsenical in shellfish extracts.