Determination of domoic acid in shellfish by liquid chromatography- tandem mass spectrometry coupled with dispersive solid phase extraction

Abstract

A method utilizing liquid chromatography-tandem mass spectrometry(LC-MS/MS) coupled with dispersive solid phase extraction for quantitative analysis of domoic acid in four kinds of shellfish was established. The sample of 0. 1 g was extracted with 25% methanol aqueous solution, the extract was purified by dispersive solid phase extraction with 50 mg HLB and 5 mg GCB, and then filtered through a PTFE membrane. The analytes were separated on a C_(18) column(100 mm×2. 1 mm, 1. 9 μm), and detected in selected reaction monitoring(SRM) mode via positive electrospray ionization. The matrix matching and external standard method was used for quantitation. Domoic acid showed good linearity in the concentration range between 1. 0 ng/mL and 50. 0 ng/mL with correlation coefficients higher than 0. 9994. The detection limits of domoic acid in shellfish was 5 μg/kg. The inter-and intra-day recoveries were 91. 6%-109. 2% and 90. 9%-109. 3%, respectively. The inter-and intra-day ralitive standard deviations(RSDs) were lower than 8. 2% at spiked concentrations of 20, 50 and 100 μg/kg. The method is accurate, fast, easy to operate, which can satisfy the requirements of public health emergency testing or routine testing.