镉试剂2B固相萃取光度法测定水中微量银

Solid Phase Extraction and Spectrophotometric Determination of Silver with Cadion 2B

研究了镉试剂2B固相萃取测定银的方法.在pH为9.5的硼砂-氢氧化钠缓冲介质中,乳化剂-OP存在下,镉试剂2B与银反应生成2:1稳定络合物,该络合物可用pH使用范围为1～12的Waters XterrarMRP18固相萃取小柱富集,小柱上富集的络合物用乙醇(内含0.01 mol/L、pH为9.5的四氢吡咯-醋酸缓冲溶液)洗脱后用光度法测定,在洗脱剂介质中最大吸收波长为555 nm,摩尔吸光系数为1.04×105 L/(mol·cm).银质量浓度在0.01～1.0μg/mL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.

The color reaction of Cadion 2B with silver（Ⅰ） was studied. In the presence of pH 9.5 borax - sodium hydroxide buffer and emulsifier- OP, Cadion 2B reacts with silver（Ⅰ） to form a stable 2 ： 1 complex, which can be extracted by Waters Xterra ^TMRP18 cartridge in pH 1 - 12 and eluted from the cartridge with ethanol（ containing 0.01 mol/L of pH 9.5 pyrrolidine - acetate buffer）, then determined by spectrophotometry. The molar absorptivity is 1.0^4 × 10^5 L · mol ^-1 · cm^-1 at 555 nm. Beer＇s law is obeyed in the silver concentra- tion range of 0.01 - 1.0 μg/mL. This method was applied to determining silver in environmental water samples with good results.