磺硝酚偶氮若丹宁固相萃取光度法测定环境样品中的铅

Study on solid phase extraction and spectrophotometric determination of lead in environmental samples with 4-nitro-6-sulfophenolazorhodanine

在pH 4.5的HAc NaAc缓冲介质中 ,吐温 - 80存在下 ,磺硝酚偶氮若丹宁 (NSPAR)与铅反应生成 2∶1稳定络合物 ,该络合物可被WatersSep PakC1 8小柱固相萃取 ,用氮 氮二甲基甲酰胺 (DMF)洗脱后用光度法测定。在洗脱液介质中 ,λmax=5 5 5nm ,体系摩尔吸光系数ε=1 .0 2× 1 0 5L·mol- 1 ·cm- 1 。铅质量浓度在 0 .0 5～ 4.0 μg/mL内符合比尔定律 。

The color reaction of lead with 4-nitro-6-sulfophenolazorhodanine (NSPAR) was studied. In the presence of pH=4.5 buffer solution and Tween-80 medium. NSPAR can react with lead(Ⅱ) to form a stable 2∶1 complex. This complex can be extracted by Waters Sep-Park-C_(18) cartridge and then eluted by DMF. The molar absorptivity is 1.02×10~5 L·moL^(-1)·cm^(-1) at 555 nm. Beer′s law is obeyed in a range of 0.05～4 μg/mL. This method can be applied to the determination of lead in environmental samples with satisfactory results.