在pH为3.5的HOAc-NaOAc缓冲介质中,吐温-80存在下,对磺酸基苯基亚甲基若丹宁(SBDR)与汞反应生成2∶1稳定络合物,该络合物可被Waters Sep-Pak-C18固相萃取小柱萃取,小柱上富集的络合物用1.0 mL无水乙醇洗脱后在乙醇介质中,于其吸收峰550 nm处用1 cm微量比色皿测定吸光度.该显色体系的表观摩尔吸光系数ε＝1.05×105L·mol-1·cm-1.汞含量在0-4 μg/50 mL内符合比耳定律,方法用于烟草中汞含量的测定,测得RSD(n=7)小于25%,回收率在97%-103%之间,测得结果与AAS法测得结果一致.

In an acetate medium of pH 3.5 and in the presence of Tween-80,a stable complex was formed by the new color reagent,p-sulfobenzylidene rhodanine (abbreviated as SBDR) with mercury(Ⅱ) having a mole ratio of (R∶Hg) 2 to 1.A solid-liquid extraction was carried out by passing the sample solution containing the SBDR-Hg complex through the solid-phase extraction column (Waters Sep-Pak-C18).The SBDR-Hg complex,which was extracted and enriched on the extraction column,was then eluted from the column with 1.0 mL of absolute alcohol,and its absorbance was measured at 550 nm (the absorption maxima of the complex in alcohol) with a 1 cm micro absorption cell.Molar absorptivity of the color system was found to be 1.05×105L·mol-1·cm-1.Beer′s law was kept in the concentration range of 0 to 4 μg of Hg(Ⅱ) in 50 mL of solution.In its application to the analysis of some tobacco samples,RSD′s (n=5) obtained were less than 2.5%,and recoveries found were in the range of 97%-103%,and the results were in conformity with those obtained by AAS method.