用分光光度法测定烟草中的汞

Determination of Mercury in Tobacco by Spectrophotometry

研究了对 -磺酸基苯基亚甲基若丹宁 (SBDR)与汞离子 (Hg2 +)的显色反应。在pH为 4 .0的HAc NaAc缓冲介质中和吐温 - 80存在下 ,SBDR与Hg2 +反应生成稳定的络合物 ,通过WatersSep Park C18固相萃取小柱萃取和无水乙醇洗脱后 ,用分光光度计测定洗脱液在λmax=5 2 0nm处的吸光度。体系ε=1.2 1× 10 5L·mol-1·cm-1,Hg2 +含量在 0 .0 1～ 1.5 μg mL内此溶液的吸光度与Hg2 +浓度的关系符合比尔定律。

The color reaction of mercury with p-Sulfobenzylidene rhodanine (SBDR) was studied. A stable complex was formed by reaction of SBDR with mercury ion (Hg+{2+}) in a pH=4.0 acetic acid-sodium acetate buffer solution at the presence of tween-80. The complex was extracted by Waters Sep-Park-C-{18} cartridge and eluted with ethanol. The absorption of the eluent was determined by spectrophotometry at 520nm of maximum wavelength. The molar absorptivity of this complex was about 1.21×10 5L5mol+{-1}5cm+{-1}. The relationship between the absorption of the eluent and its Hg+{2+} concentration observed the Beers law when the concentration of mercury ion was in the range of {0.01} to 1.50μg/ml. The contents of mercury in several tobacco leaves were determined.