原子荧光法测定血中锡的湿式消解法之优化

目的建立适合于基础实验室应用的原子荧光法测定血中锡时的湿式消解方法。方法取人体1 mL全血,分别使用硝酸、盐酸、硫酸、过氧化氢以不同比例混合,置于石墨消解仪于90℃对血样进行消解,消解完成后加入200 g/L硫脲-抗坏血酸1 mL来掩蔽镍、铁、砷、硒等干扰离子,使用体积分数4%的盐酸溶液定容至10 mL,采用氢化物发生-原子荧光法测定锡浓度。结果依据不同消解组合的结果,提出优化的湿式消解方法为硝酸2 mL加过氧化氢2 mL于90℃消解样品1 h。在此条件下,质量浓度在4.00~200.00μg/L范围内,原子荧光法测定锡的标准曲线线性关系良好,相关系数为0.999 5;方法检出限为0.20μg/L,加标回收率为99.76%~105.72%,批内精密度为0.21%~2.59%。结论该湿式消解方法可使样品消解完全,待测元素损失少,基体干扰少,准确度和精密度较好,所用消解仪器便宜且在基层容易普及,适用于基层实验室对人血中锡浓度的测定。

Optimization of wet digestion method for determination of tin in blood by atomic fluorescence spectrometry

  Objective  To establish a wet digestion method for the determination of tin in blood by atomic fluorescence spectrometry.  Methods  One mL whole blood was collected and mixed with nitric acid, hydrochloric acid, sulfuric acid and hydrogen peroxide in different proportions. The blood sample was digested at 90 ℃ by graphite digestion apparatus. After digestion, 1 mL thiourea ascorbic acid solution was added to mask nickel, iron, arsenic, selenium and other interfering ions. The volume was made up to 10 mL with 4% hydrochloric acid solution. The tin concentration was determined by hydride generation atomic fluorescence spectrometry.  Results  Based on the results of different digestion combinations, The optimized wet digestion method was to add 2 mL hydrogen peroxide to 2 mL nitric acid, and then digested the sample at 90 ℃ for 1 h.Under this condition, the linear range of tin in blood was 4.00 - 200.00 g/L, the correlation coefficient was 0.999 5;the detection limit was 0.20 g/L, the recovery was 99.76% - 105.72%, and the RSD was 0.21% - 2.59%. The sample could be stored for 7 days at 4 ℃.  Conclusions  This wet digestion method can achieve the sample complete digestion, with minimum loss of target analyte and low matrix interference, and it also has good accuracy and precision. What's more, the digestion instrument used in this method is affordable and widely used in the grass-roots laboratories, which is suitable for the determination of tin concentration in human blood.