尿中砷的高压快速消解原子荧光分光光度法

目的建立一种快速去除尿中砷检测时硝酸和亚硝酸干扰的原子荧光分光光度计方法。方法采用高压消解罐对样品进行消解，加尿素去除消解液中的亚硝酸，加氢氧化钠中和消解液中和过量的硝酸，加混合预还原剂（半胱氨酸-硫脲）和盐酸，以硼氢化钾为还原剂，测定尿中砷。结果在选定的操作条件下，砷的最低检出限为0.034μg/L，回收率＞95%，相对标准偏差＜2%。结论用该法测定尿中的砷操作简单，灵敏度高，检出限低，结果令人满意。

标签：高压消解；原子荧光；尿；砷

Determination of arsenic in urines quickly by hydride generation atomic fluorescence spectrometry assisted high pressure digestion

ZHANG?Weilai

Centers for Disease Control and Prevention of Hongqiao District of Tianjin City, Tianjin 300132,China

[Abstract] Objective To develop a method to determine trace arsenic in urines quickly by hydride generation atomic fluorescence spectrometry assisted high pressure digestion. Methods The samples were treated by pressure digestion，urea was used to dislodge nitrous acid, sodium hydroxide was used to neutralize excess nitric acid. The mixture of cysteine and thiourea were used fits reducing agent. Potassium borohydride was used reducing agent. Detect the arsenic in urines. Results In the operating conditions of choice, the detection limit of the method was 0.034μg/L，the recovery rate was greater than??95%,the relative standard deviation was less than 2%. Conclusion The method is rapid，accurate and reliable，which can meet the requirements for determination of arsenic in urines.

[Key words] High pressure digestion;HG-AFS;Urine;Arsenic

砷及其化合物为致癌物质，人体摄入的砷主要从尿排出，可以通过尿砷浓度的测定推测被检者近期砷摄入的情况。尿砷的测定方法有银盐法、石墨炉原子吸收分光光度法、原子荧光法等。随着原子荧光光度计的推广，原子荧光法得到大量的应用。原子荧光法测尿中砷的重点是消解及消解后的处理，笔者研究了一种简单而有效的检测方法，现报道如下。

1?材料与方法

1.1?原理

尿样经加酸消解后，在酸性介质中以半胱氨酸和硫脲为预还原剂将五价砷还原为三价砷，再以硼氢化钾将三价砷还原为砷化氢，由载气（氩气）带入原子化器中，在砷空心阴极灯的照射下，发出特征波长的荧光，测得样液中的砷含量。

1.2?仪器与试剂

AFS-9900四道原子荧光光度计（西安科创海光仪器有限公司），砷空心阴极灯（西安科创海光仪器有限公司），砷标准溶液（100μg/mL，国家环保总局标准样品研究所，GSB07-1275-2000），所用试剂均为分析醇。

1.3?试剂的处理

1.3.1?砷标准储备液（10.0μg/mL）?吸取10.0 mL浓度为100.0μg/mL的砷标准溶液置于100 mL的容量瓶中，向瓶中加入

2.0 mL浓盐酸，再用去离子水定容至刻度。