固相萃取光度法测定环境水样中镉(Ⅱ)的研究

Study on solid phase extraction and spectrophotometric determination of cadmium in environmental waters

摘要: 研究了用3,5-二溴-2-吡啶偶氮重氮氨基偶氮苯(3,5-DB-PDAB)固相萃取光度法测定镉(Ⅱ).在pH=10的硼砂-氢氧化钠缓冲介质中,TritonX-100存在下,3,5-DB-PDAB与镉(Ⅱ)反应生成2:1稳定配合物,体系最大吸收波长为530 nm,摩尔吸光系数ε=1.62×105L/(mol·cm),环境水样中的镉(Ⅱ)用强阴离子交换固相萃取柱固相萃取预分离和富集后用该方法测定,方法简单,准确度高,回收率96%～10%,相对标准偏差小于3.5%.

Abstract: It was studied that the solid phase extraction and spectrophotometric determination of cadmium (Ⅱ) with 3,5-dibromomine-2-pyridinediazoaminoazobenzene(3,5-DB-PDAB) as complexing agent.3,5-DB-PDAB can react with cadmium(Ⅱ) to form a stable 2:1 complex(3,5-DB-PDAB:Cd(Ⅱ)) in a medium of pH=10 buffer solution and Triton X-100.The molar absorptivity of the complex is 1.62×105L/(mol·cm) at 530nm.Beer’s law is obeyed in range of 0-1.0μg/mL cadmium(Ⅱ).The cadmium(Ⅱ)ion in samples can be enriched and separated by solid phase extraction with anion exchange resin cartridge.This method is simple and precise and can be applied to do determine cadmium(Ⅱ) in water.A recovery in a range of 96%-104% and a RSD of less than 3.5% were obtained.