oa South African Journal of Chemistry - Study on the solid phase extraction and spectrophotometric determination of mercury in water and biological samples with 5-(p-aminobenzylidene)-thiorhodanine
This paper presents the synthesis and application of 5-(p-aminobenzylidene)-thiorhodanine (ABTR) as a new chromogenic reagent for the determination of mercury. Based on the rapid reaction of mercury(II) with ABTR and the solid phase extraction of the coloured chelate with a C18 disk, a highly sensitive, selective and rapid method for the determination of mercury has been developed. In the presence of pH 3.5 sodium acetate-acetic acid buffer solution and emulsifier-OP medium, ABTR reacted with mercury(II) to form a red chelate in a molar ratio 1:2 (mercury to ABTR). This chelate was enriched by solid phase extraction with a C18 disk and eluted from the disk with dimethyl formamide (DMF). An enrichment factor of 50 was achieved. The molar absorptivity of the chelate in DMF was found to be 1.21 x 105 L mol-1 cm-1 at 555 nm. Beer's law was obeyed in the range of 0.01~ 3 µg mL-1. The relative standard deviation for eleven replicates with a concentration of 0.01 µg mL-1 was 1.98%. This method was applied with good results to the determination of mercury in water and biological samples.
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