对磺酸基苯基亚甲基若丹宁固相萃取光度法测定银

研究了对磺酸基苯基亚甲基若丹宁(SBDR)与银的显色反应，在pH为2.6的柠檬酸-氢氧化钠缓冲介质中，吐温-80存在下, SBDR与银反应生成2∶1稳定络合物，该络合物可用Waters Porapak Sep-Park固相萃取小柱富集，用乙醇(含5％乙酸)溶液洗脱后用光度法测定，在乙醇介质中λ_max＝520 nm，摩尔吸光吸数ε＝7.53×104 L·mol-1·cm-1。银含量在0～1.2 μg·(25 mL)-1内符合比尔定律，方法用于环境水样中银含量的测定，结果令人满意。

Study on Solid-Phase-Extraction Spectrophotometric Determination of Silver with p-Sulfobenzylidene-Rhodanine

The color reaction of silver with p-sulfobenzylidene-rhodanine (SBDR) was studied. Based on the color reaction of SBDR with silver (I) and the solid phase extraction of its colored complex with Waters Porapak Sep-Park-C18 cartridge, a new method for the determination of micro-amount of silver (I) was studied. In the presence of pH = 2.8 citric acid-sodium hydroxide buffer solution and Tween-80 medium, SBDR can react with silver (I) to form a stable 2:1 complex. The colored complex can be extracted by C18 cartridge and eluted by ethanol (containing 5% acetic acid), and then can be determined by spectrophotometry. The molar absorptivity is 7.53 x 10(4) L x mol(-1) x cm(-1) at 520 nm. Beer's law is obeyed in the range of 0-1.2 microg x (25 mL)(-1). This method can be applied to the determination of silver in water with satisfactory results.