Development and validation of a new analytical approach for simultaneous speciation analysis of Hg and Se in fishery products by HPLC-ICP-MS

This study reports the development and validation of a new analytical method for the simultaneous speciation analysis of Se and Hg in fish muscle.For this purpose, four Se species (Se(IV), Se(VI), Se-methionine/SeMet and Se-cysteine/SeCys) and two Hg species (Hg(II) and methylmercury/MeHg) were extracted simultaneously by microwave assisted enzymatic hydrolysis (using protease XIV at pH 7 and 2-mercaptoethanol) and then separated in less than 15 min by using a mixed mechanism anion-cation exchange HPLC with a mobile phase consisting of a mixture of methanol 5% (v/v), 45 mM HNO3, 0,015% 2-mercaptoethanol and 1,5 mM sodium 3-mercapto-1-propanesulfonate.The separated species were detected online by inductively coupled plasmamass spectrometry.The speciation method was validated by means of the accuracy profile approach by carrying out 3 measurement series in duplicate on (3) different days over a time-span of 3 weeks.The quantification limits (LQ) are in the range of 0.055-CV_R was 3%.The method was successfully applied to the analysis of muscle samples from four different fish species: rainbow trout, tuna, swordfish and dogfish.