湿法消解氢化物发生-原子荧光光谱法测定尿中砷

Wet Digestion Hydride Generation-Atomic Fluorescence Spectrometry for Determination of Arsenic in Urine

目的建立原子荧光光谱法测定尿砷浓度的方法。方法尿样品经混合酸消化后,加入硫脲和抗坏血酸使五价砷预还原为三价砷,再加入硼氢化钠或硼氢化钾还原生成砷化氢,由氩气载入石英原子化器中分解为原子态砷,在砷空心阴极灯发射的光的激发下产生原子荧光,荧光强度可与标准系列比较定量。分析样品的消化、预还原剂浓度、还原剂浓度、酸度等因素对测定的影响。结果砷的浓度在0.0～50.0μg/L内线性关系较好,相关系数为0.999 0～0.999 9;最低检出限为0.068μg/L;相对标准偏差为2.1%～3.1%;加标回收率为92.5%～102.0%。结论湿法消解氢化物发生-原子荧光光谱法测定尿砷具有操作简单、实用、快速、准确、灵敏度高、基体干扰少,便于推广运用,特别适用于大批量人尿砷的测定。

Objective To establish atomic fluorescence spectrometry for determining the concentration of urinary arsenic. Methods Urine samples digested by the mixed acid were treated with thiourea and ascorbic acid to make the pre-redueed pentavalent arsenic to be trivalent arsenic ,then sodium borohydride or potassium borohydride was added and reduced to arsine,loaded into quartz atomizer by the argon and decomposed into arsenic atom. Atomic fluorescence was generated under the excitation of light emitted by the arsenic hollow cathode lamp,whose intensity was compared with a standard series. To analyze the effects of some factors,including digestion of sample, pre-reducing agent concentration, reductant concentration and acidity,on the determination. Results The concentration of arsenic in range of 0.0 - 50.0 p^L had good linearity,with a correlation coetticient of 0. 9990 - 0. 9999 ;The minimum detection limit was 0. 068 ix~/L;The relative standard deviation ranged from 2.1% to 3.1% ;The recovery rate ranged from 92.5% to 102.0%. Conclusion Wet digestion hydride generation-atomic fluorescence spectrometry for determination of arsenic in urine is simple, practical,fast,accurate, of high sensitivity and less interference from the matrix, which is easy to be popularized and applied, especially suitable for the determination of urine arsenic in a large quantity of people.