Toward a routine methodology for speciation analysis of methylmercury in fishery products by HPLC coupled to ICP-MS following the validation based on the accuracy profile approach

Abstract

ABSTRACT A simple, rapid and robust method for routine speciation analysis of methylmercury (MeHg) by reversed phase high-performance liquid chromatography coupled to inductively coupled plasma-mass spectrometry (RP HPLC-ICP-MS) following closed microwave-assisted extraction was optimised and validated using the accuracy profile approach. An effective separation of MeHg from its inorganic Hg precursor (Hg2+) was achieved in less than 3 min using RP HPLC by means of a peptide mapping column. A robust method validation was carried out using the accuracy profile approach by carrying out seven measurement series in duplicate on (seven) different days over a timespan of 2 months by two different operators. The measurement bias corresponding to the validity domain ranged from −0.2% to 2%, whereas the coefficient of variation in terms of repeatability (CVr) varied from 1.5% to 8.3% (depending on the analyte level) while the coefficient of variation in terms of intermediate reproducibility (CVR) ranged from 3.6% to 8.3%. The limit of quantification was 0.0032 mg kg−1 (wet weight). This novel approach was proved to be highly robust and suitable for the routine determination of MeHg in fishery products with satisfactory analytical performances in order to accurately assess the risks related to MeHg due to the consumption of this type of foodstuffs.