Two novel thio-arsenosugars in scallops identified with HPLC-ICPMS and HPLC-ESMS

Two new thio-arsenosugars were identified in aqueous and methanol extracts from the gonad and the muscle of the great scallop by using high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICPMS) and HPLC-electrospray ionization mass spectrometry (ESMS). The gonad of the scallops contained thio-arsenosugar-sulfonate [0.067 mg (As) kg(-1); dry mass +/- 3.7%] and thio-arsenosugar-sulfate [0.267 mg (As) kg(-1); dry mass +/- 1.2%]. The muscle also contained both thio-arsenosugar-sulfonate [0.030 mg(As)kg(-1); dry mass +/- 2.6%] and thio-arsenosugar-sulfate [0.200 mg(As)kg(-1); dry mass +/- 2.6%]. Methanol increased the extraction efficiency threefold for the two thio-arsenosugars as compared to water. Fresh and freeze-dried samples from both parts of the scallop showed no significant difference with respect to the concentration of the two thio-arsenosugars. In order to confirm the presence of the thio-arsenosugars, a new method for their determination with HPLC-ESMS was developed. Under optimized conditions [Hamilton PRP-X100; 150 by 1.0 mm; 20 mM NH4HCO3 with 55% (v/v) methanol at pH 10.3] we succeeded in determining the pseudomolecular ions of thio-arsenosugar-glycerol, thio-arsenosugar-phosphate, thio-arsenosugar-sulfonate, and thio-arseno sugar-sulfate at concentrations less than 5 mu g (As) dm(-3) in standard solutions and real samples.