[Study on the solid phase extraction spectrophotometric determination of mercury in water with 5-(2-hydroxy-4-sulfo-5-chlorophenol-1-azo)-thiorhodanine].

Based on the color reaction of mercurywith 5-(2-hydroxy-4-sulfo-5-chlorophenol-1-azo)-thiorhodanine (HSTC) and the solid phase extraction of the colored complex with C18 cartridge, a new method for the determinations microg x L(-1) level of mercury was studied. In the presence of pH 3.6 HAc-NaAc buffer solution. HSTC reacted with mercury (II) to form a stable 2:1 complex. This complex was enriched by solid phase extraction with C18 cartridge and the retained complex from cartridge was eluted with DMF. An enrichment factor of 80 was achieved. In the measured solution, the molar absorptivity was 6.24 x 10(4) L x moL(-1) x cm(-1) at 545 nm. Beer's law was obeyed in the range of 0-1.5 microg x mL(-1). This method was applied to the determination of mercury in water. The relative standard devitions were 1.8%-2.2% and the recoveries were 93%-106%. The results are satisfactory.