环境水样中痕量砷(Ⅲ)的动力学荧光测定法

Determination of trace arsenic (Ⅲ) in water by kinetic fluorimetry

目的建立环境水样中痕量砷(Ⅲ)的动力学荧光测定法。方法水样经消化处理和离子交换树脂后,加入1.0×10-4mol/L的二氯荧光素溶液0.6 ml、0.1 mol/L盐酸溶液1.5 ml和1.0×10-3mol/L碘酸钾溶液0.8 ml,沸水浴中反应10 min后冷却;并设立试剂空白。以438 nm激发波长,512 nm发射波长处测定荧光强度(F)。结果在2.0～200μg/L范围内,所得砷(Ⅲ)的回归方程为ΔF=1.754 9+0.177 8 c,r=0.998 6,呈良好的线性关系。该方法的检出限为0.5μg/L,加标回收率在96.8%～102.1%之间,RSD为2.5%～3.4%。结论该方法具有快速、简便、灵敏度高、选择性好等优点,适用于环境水样中砷(Ⅲ)的测定。

Objective To establish kinetic fluorimetric method for the determination of trace arsenic （Ⅲ） in water. Methods After digestion and treatment by ion exchange resin, 0.6 ml 1.0 ×l0-4 mol/L diehlorofluorescein solution,l.5 ml 0.1 mol/L hydrochloric acid solution and 0.8 ml 1.0×l0-3 mol/L potassium iodate solution were added into water samples, then were cooled after heating for 10 min in boiling water bath, and the reagent blank was established. The fluorescence intensity （F） was determined at 438 nm excitation wavelength and 512 nm emission wavelength. Results A good linear relationship was achieved in the range of 2.0-200 μg/L with a regression equation △F=1.754 9＋0.177 8 c ,r=0.998 6. The limit of detection was 0.5 μg/L. The recovery rates were in the range of 96.8%-102.1% ,and the relative standard deviation were 2.5%-3.4%. Conclusion The method possesses several advantages including rapid, simple, high sensitivity and good selectivity, and is applicable to the determination of arsenic（Ⅲ ） in water.