A new method for preconcentration and determination of mercury in fish, shellfish and saliva by cold vapour atomic absorption spectrometry

The development of a method using solid phase extraction for preconcentration and determination of mercury by cold vapour atomic absorption spectrometry is described. Hg (II) ions are sorbed on a minicolumn packed with Amberlite XAD-4 sorbent functionalised with 2-(2′-benzothiazolylazo)-p-cresol (BTAC). Then, a reducing solution was used for desorption and the transport of the analyte for subsequent detection. The assay presented a limit of detection of 0.011 μg L−1 (0.011 μg g−1, for solid samples), a limit of quantification of 0.038 μg L−1 (0.038 μg g−1, for solid samples), a precision of 0.50% (1.000 μg L−1 Hg solution) and an enrichment factor of 46. The proposed method was applied to the determination of mercury in human saliva (0.055-0.200 μg L−1). The following seafood collected in Todos os Santos Bay, Brazil was also analysed: bass (0.169-0.195 μg g−1), mullet (0.043-0.361 μg g−1), shrimp (0.075-0.374 μg g−1) and mussel (0.206-0.397 μg g−1).