SOP for Manual MeHg by ICPMS isotope dilution

Standard Operating Procedure for the Determination of Methyl Mercury by Aqueous Phase Ethylation, Followed by Gas Chromatography Separation with Speciated Isotope Dilution Mass Spectrometry.

Water samples are spiked with isotopically enriched standard and distilled to remove potential interferences. The pH of the distillate is adjusted to 4.9 using acetate buffer. The distillate is then ethylated using sodium tetraethyl borate (NaTEB4) and allowed to react for 15 minutes. Following reaction with NaTEB the distillate is purged with grade 5 Argon gas (Ar) for 20 minutes and the ethylated mercury species are collected on a Carbotrap. The ethylated mercury species are thermally desorbed from the Carbotrap, separated using a gas chromatography (GC) column, reduced and ionized using the ICP-MS, and detected using Speciated Isotope Dilution Mass Spectrometry (SIDMS).

Mercury Research Laboratory