对氨基苯基亚甲基若丹宁固相萃取光度法测定银

Determination of Silver by Solid Phase Extraction Spectrophotometry with 5-(p-Aminobenzylidene)-Rhodanine

在 p H为 2 .6的柠檬酸 -氢氧化钠缓冲介质中 ,乳化剂 - OP存在下 ,对氨基苯基亚甲基若丹宁 (ABR)与银反应生成 2∶ 1的稳定络合物 ,该络合物可用 C18固相萃取小柱富集 ,用乙醇 (含 5 %乙酸 )洗脱后由光度法测定 ,在乙醇介质中 λmax=5 30 nm,ε=5 .5 3× 10 4L·mol-1·cm-1。银含量在 0— 2 μg/ m L范围内符合比耳定律。方法用于环境水样中银含量的测定 。

In pH=2.6 citric acid-sodium hydroxide buffer solution and emulsifier-OP medium,5-(p-aminobenzylidene)-rhodanine (ABR) can react with silver(Ⅰ) to form a stable 2∶1 complex.The colored complex can be extracted by C 18 cartridge and eluted from the cartridge by ethanol (containing 5% acetic acid), then determined by spectrophotometry. The molar absorptivity is 5.53×10 4L·mol -1·cm -1 at 530nm. Beer's law is obeyed in the range of 0-2μg/mL.This method was applied to the determination of silver in water with good results.