CRYOFOCUSING COUPLED TO ATOMIC-ABSORPTION SPECTROMETRY FOR RAPID AND SIMPLE MERCURY SPECIATION IN ENVIRONMENTAL MATRICES

A fully automated on-line hyphenated system for mercury speciation ana lysis in environmental samples is presented. It provides derivatizatio n by hydride generation or ethylation, preconcentration by cryotrappiu g, separation by packed column gas chromatography and detection by qua rtz furnace atomic absorption spectrometry, Automation of the hyphenat ion results in improved reproducibility of the analysis, The system ha s been specifically optimised for analysis of mercury compounds, but i t is also potentially operative for other hydride- or ethylated deriva tive-forming elements, after the corresponding optimisation, Main adva ntages and potential Limitations of the system are discussed. General procedures for the analysis of both solid (sediments, biotissues, susp ended particulate matter) and liquid (sea and fresh mater) samples are proposed and validated by analysis of certified reference materials. The obtained methylmercury and inorganic mercury concentrations are in agreement with the certified values. Detection limits of the method h ave been estimated as 0.5 ng g(-1), 3 ng g(-1), 0.1 ng l(-1) for both mercury species in dry sediments, biological tissues and aqueous sampl es, respectively. Analysis of one sample only requires 10 min (hydride generation) or 20 min (ethylation), so that a sample throughout of 6 or 3 samples h(-1), respectively, may be achieved. Results from the an alysts of real samples collected in the Gironde and Scheldt estuaries (sediments, suspended particulate matter, water and biological tissues ) are also provided.