Mercury speciation in environmental samples by cold vapour atomic absorption spectrometry with in situ preconcentration on a gold trap.

A method for total and organic mercury determination, which takes in to account all the phases of the analytical procedure, has been developed. In particular, conditions for mercury reduction were optimized by a central composite design. The pre concentration of the analyte has been achieved by amalgamation on a gold trap system developed in our laboratories, consisting in a pyrolitic graphite platform winded by a gold wire. Moreover, as regards organic mercury, a microwave assisted mineralization of the organometallic form, after its extraction from the matrix, is proposed. This method guaranties the full transformation in Hg(II) and, consequently, the quantitative reduction to elemental mercury, allowing the application of Cold Vapour –Atomic Absorption Spectrometry for its determination. The resulting analytical performance of the optimized method was adequate for the determination of mercury species in environmental and biological samples.