Study on the solid phase extraction of Hg(II)-ABR chelate with C18 disks and its application to the determination of mercury in tobacco and tobacco additives

A highly sensitive, selective and rapid method for the determination of mercury based on the rapid reaction of mercury(II) with 5-(p-aminobenzylidene)-rhodanine (ABR) and the solid phase extraction of the colored chelate with C,8 disks has been developed. In the presence of pH = 3.5 sodium acetate-acetic acid buffer solution and Emulsifier-OP medium, ABR reacts with mercury(II) to form a red chelate of a molar ratio 1:2 (mercury to ABR). This chelate was enriched by the solid phase extraction with C-18 disks and eluted the retained chelate from the disks with dimethyl formamide (DMF). The enrichment factor of 50 was achieved. In the DMF medium, the molar absorptivity of the chelate is 1.16 x 10(5) L.mol(-1).cm(-1) at 540 nm. Beer's law is obeyed in the range of 0.01similar to3 mug/mL in the measured solution. The relative standard deviation for eleven replicated samples of 0.01 mug/mL level is 1.83%. This method was applied to the determination of mercury in tobacco and tobacco additives with good results.