2-[2-(5-溴喹啉)-偶氮]-5-二乙氨基苯酚固相萃取光度法测定环境样品中镉的研究

合成了新试剂2-2-(5-溴喹啉)-偶氮]-5-二乙氨基苯酚(5-Br-QADEAP),试剂结构通过元素分析,红外光谱和核磁共振氢谱鉴定.研究了5-Br-QADEAP与镉的显色反应,在pH 8.0的硼酸-氢氧化钠缓冲介质中,Triton X-100存在下,5-Br-QADEAP与镉反应生成2:1稳定络合物,体系最大吸收波长λmax=595nm,摩尔吸光系数e=1.60×105L·mol-1·cm-1,样品中的镉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,方法相对标准偏差在2.5%～3.2%之间,标准回收率在96%～105%,结果令人满意.

Study on Solid Phase Extraction and Spectrophotometric Determination of Cadmium with 2- [2- (5-Bromoquinolinylazo) ]-5-Diethylaminophenol

A new chromogenic reagent 2-2-(5-bromoquinolinylazo)]-5-diethylaminophenol (5-Br-QADEAP) was synthesized, and its structure was verified by elemental analysis, infrared spectrum, and 1H nuclear magnetic resonance spectrum. The color reaction of 5-Br-QADEAP with cadmium was studied. In the presence of pH 8.0 buffer solution and Triton X-100 medium, 5-Br-QADEAP can react with cadmium(II) to form a stable 2 : 1 complex (5-Br-QADEAP: Cd(II). The molar absorptivity is 1.60 x 10(5) L x mol(-1) x cm(-1) at 595 nm. Beer's law is obeyed in the range of 0-1.0 microg x mL(-1). The cadmium ion in the samples can be enriched and separated by solid phase extraction with anion exchange resin cartridge. This method was applied to the determination of cadmium in water and food. The relative standard deviations are 2.5%-3.2%, and the recoveries are 96%-105%. The results are satisfactory.