二溴羟基苯基荧光酮分光光度法测定汞(Ⅱ)——经巯基葡聚糖凝胶柱分离富集

Spectrophotometric Determination of Mercury(Ⅱ) with Color Reagent DBHPF After Separation and Enrichment on Sulfhydryl Dextran Gel Column

在以硼酸盐缓冲溶液控制于pH 9.1的由十六烷基三甲基溴化铵(CTMAB)、正丁醇、正庚烷和水以1.0比0.9比0.1比9.8的质量比配制的微乳溶液中,汞(Ⅱ)与二溴羟基苯基荧光酮(DBHPF)反应形成1比2的橙色络合物,络合物的最大吸收峰位于570 nm波长处,表观摩尔吸光率为3.2×10~5 L·mol^(-1)·cm^(-1)。汞(Ⅱ)的质量浓度在6～550μg·L^(-1)范围内符合比耳定律,检出限(3S/N)为2μg·L^(-1)。据此提出了测定痕量汞(Ⅱ)的方法。应用此方法测定了水样中汞(Ⅱ)并作方法的回收率及精密度试验,测得平均回收率为104%,相对标准偏差(n=6)为2.7%(两个样品的平均值)。对水样中痕量汞(Ⅱ)的分离和富集,建议采用巯基葡聚糖凝胶吸附分离法,吸附于凝胶柱上的汞(Ⅱ)用氯化钠饱和的8 mol·L^(-1)盐酸溶液洗脱后按上述光度法测定。

In a microemulsoid medium containing CTMAB, n-butanol, n-heptane and water, mixed in the mass ratio of 1.0 to 0. 9 to 0. 1 to 9. 8, and buffered at pH 9. 1 with borax buffer solution, an orange colored complex （Hg：R = 1 ： 2） was formed by the reaction of Hg （Ⅱ） ion with dibromohydroxyphenylfluorone （DBHPF）, having its absorption maximum at the wavelength of 570 um and its apparent molar absorptivity （ε570） of 3. 2×10^5L·mol^-1·cm^-1. Beer＇s law was kept in the range of 6--550 μg·L^-1 of Hg（Ⅱ）. Detection limit （3S/ N） of the method was found to be 2μg·L^-1. Based on these facts, a method for determination of traces of Hg（Ⅱ） was proposed. Tests for recovery and precision were made by analyzing 2 water samples, giving values of average recovery and average RSD＇s （n= 6） to be 104% and 2. 7% respectively. Procedure for enrichment of traces of Hg（Ⅱ） in water sample by adsorption on sulfhydryl dextran gel （SDG） column and elution from the column by 8 mol·L^-1 HC1 saturated with NaCl was given in detail.