THE SPECIATION OF MERCURY AND ORGANOMERCURY COMPOUNDS BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY ATMOSPHERIC-PRESSURE IONIZATION MASS-SPECTROMETRY

A method for the structural confirmation of mercury (II) chloride and organomercury (II) chlorides (monomethylmercury chloride, monoethylmer cury chloride and monophenylmercury chloride) employing liquid chromat ography coupled to atmospheric pressure ionization mass spectrometry w as developed. The chromatographic system comprised a Kromasil 100-5C18 , 5 mu m (250 x 4.6 mm) column and a mobile phase of 2-mercaptoethanol (0.01% v/v) in methanol: water (1:1 v/v), at a flow rate of 1 mL min( -1). The optimization of the API-MS conditions is discussed, together with the fragmentation patterns observed for standards. No peaks due t o the molecular ion were present and the most intense peaks were due t o [M + mercaptoethanol](+) or [M + 2 mercaptoethanol - H](+). The qual itative analysis of fish tissue spiked with methylmercury (II) chlorid e, using selected ion monitoring (SIM), is discussed. (C) 1998 LGC (Te ddington) Ltd.