对羧基苯偶氮硫代若丹宁固相萃取光度法测定烟草及其添加剂中的汞

Study on Solid Phase Extraction and Spectrophotometric Determination of Mercury in Tobacco and Tobacco Additive with p-Carboxylphenylazo-Thiorhodanine

研究了对羧基苯偶氮硫代若丹宁(CPATR)与汞的显色反应,在pH为3.5 的醋酸醋酸钠缓冲介质中,吐温80存在下, CPATR与汞反应生成2∶1稳定络合物,该络合物可被Waters Sep Pak C18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 = 535 nm,体系摩尔吸光系数达8 70×103 m2/mol. 汞的质量浓度在0 05~4 0 mg/L内符合比尔定律. 该方法可用于烟草及其添加剂中汞含量的测定,结果满意.

The color reaction of mercury with p-carboxylphenylazo-thiorhodanine (CPATR) was studied. In the presence of pH=3.5 buffer solution and Tween-80 medium, CPATR can react with mercury (Ⅱ) to form a stable 2∶1 complex. This complex can be extracted by Waters Sep-Pak-C (18) cartridge and eluted the retained chelate by DMF.The molarabsorptivity is 8 70×10^(3 )m^2/mol at 535 nm. Beer's law is obeyed in range of 0.05~4 0 mg/L. This method can be applied to the determination of mercury in tobacco and its additivewith satisfactory results.