阴离子树脂微柱在线预富集火焰原子吸收法测定痕量镉

建立了流动注射在线微柱预富集-火焰原子吸收(FAAS)法测定天然水中痕量镉的体系.在溶液pH7.2条件下，8-羟基喹啉-5-磺酸与Cd2+形成的络阴离子被填有阴离子树脂的微柱吸附而富集.用1mol/L硝酸溶液洗脱树脂上所吸附的镉.洗脱液在线输入FAAS测定.当采样速率为24次/时，富集倍数为10，检出限0.5μg/L，工作曲线线性范围0～100μg/L，RSD为1.0%(n=11,Cd2+浓度为100μg/L).本体系已用于天然水样中痕量镉测定，回收率90%～106%.

Flow Injection on line Preconcentration with Anion exchange resin and Flame Atomic Absorption Spectrometric Determination of Trace Cadmium

A flow injection on-line micro-column preconcentration system with anionexchange- resin being used as sorbent was developed for flame atomic absorption spectrometric (FAAS) determination of trace cadmium. Cadmium ion was on-line reacted with the chelating reagent of 8-hydroxylquinoline-5-sulphonic acid(OXS) in the condition of pH 7.2 to form a complex anion,which was then retained on a micro-column packed with D-290 anion-exchangeresin. The retained cadmium species was eluted with a nitric acid solution of 1 mol.L-1,and the elutant was directly transported into the nebulizer of the FAAS. Under the optimized conditions, an enrichment factor of 10 was achieved for a loading period of 120 seconds,and a detection limit of 0.5 μg.L-1 and a relative standard deviation of 1.0% for eleven determinations of 0.1 mg.L-1 cadmium standard solution were obtained at the sampling frequency of 24 h-1. The proposed method has been applied to determine the trace amount of cadmium in fresh water samples.