γ-氧化铝低压柱富集-流动注射检测六价铬

Preconcentration Using Low Pressure γ-Al_2O_3 Column for the Determination of Hexavalent Chromium by Flow Injection Spectrophotometry

本研究基于低压γ-氧化铝浓缩柱与流动注射分光光度法联用,成功用于天然水样中痕量六价铬的分析检测。对于研究中的相关影响参数,如γ-氧化铝颗粒尺寸、试样酸度、脱吸附溶液中乙二胺四乙酸（EDTA）浓度、显色液中硫酸,丙酮浓度以及其它离子对实验的影响进行了仔细研究。六价铬浓度在0.1～8μg/L范围内符合朗伯-比尔定律,回归方程为H=5919C＋3604,判定系数R2=0.999,检测限为0.03μg/L（3σ）。当检测1μg/L六价铬的相关标准偏差为3.88%,浓缩系数为10.6。将本方法应用于环境样品检测时加标回收率为85%～100%。

A flow injection technique based on an online low pressure γ-Al_2O_3 column preconcentration system coupled with flow injection spectrophotometry was developed for the determination of hexavalent chromium in water samples. The influence of various parameters, such as particle size of γ-Al_2O_3 powders, acidity of adsorption solution, ethylene diamine tetraacetic acid of desorption solution, concentration of sulfuric acid and acetone in color reagent, effect of diverse ions,etc. have been studied in detail. The calibration graph was linear in the range 0.1-8.0 μg/L of hexavalent chromium, limit of detection（3σ） was 0.03 μg/L and the relative standard deviation was 3.88% for the determination of 1 μg/L of hexavalent chromium（n =10）. The enrichment factor was found to be 10.6. The validity of the proposed method was checked in ambient water samples, it was show that the recoveries of water samples were in a range of 85%-100%.