Flow injection-liquid chromatography-cold vapour atomic absorption spectrometry for rapid determination of methyl and inorganic mercury

A previously described system for determining low concentrations of mercury species in environmental samples using flow injection high-performance liquid chromatography cold vapour atomic absorption spectrometry (FI-HPLC-CVAAS) has been further developed with respect to time of analysis, long term signal stability, memory effects, detection limits, and environmental friendliness. Methyl and inorganic mercury were determined without pre-treatment in brackish water and in digested biological certified reference materials, DOLT-2 and TORT-2. Results were compared with those obtained by gas chromatography microwave-induced plasma atomic emission spectroscopy (GC-MIP-AES) using either butylation with a Grignard reagent or ethylation with sodium tetraethylborate. With the FI-HPLC-CVAAS system, absolute detection limits are 1.7 pg and 3.4 pg for methyl and inorganic mercury, respectively. Mercury species in a sample can be determined at the 0.4 ng l(-1) level within 5 min. For lower concentrations the time for analysis has to be increased.