离子交换分离石墨炉原子吸收光谱法测定高纯铟中痕量铅

样品经盐酸溶解、阳离子交换树脂分离并将试液蒸发浓缩后,用石墨炉原子吸收光谱法测定了高纯铟中的痕量铅。探讨了溶样方法、离子交换分离和测定铅的条件。结果表明:用8 mL盐酸将1 g样品溶解,以0.5 mol/L 盐酸作为淋洗液进行离子交换可把绝大部分铟基体及样品中痕量的银、砷、镉、硅分离除去,随后用2.0 mol/L 盐酸可洗脱铅。干扰试验表明,铝、铜、铁、镁、镍、锡、铊、锌与小于10 μg的铟虽然不能与铅分离,但对测定无影响。当称样量为1 g,定容体积为1.0 mL,进样量为50 μL时,方法线性范围为0.5～4.0 ng/mL,测定下限为0.000 6 μg/g,比行业标准方法 YS/T 230.1-1994的0.1 μg/g低3个数量级。方法用于实际样品分析,结果与电感耦合等离子体质谱法(ICP-MS)相符,相对标准偏差(RSD,n=8)在1.1%～19.7%之间,加标回收率为92%～120%。

Determination of trace lead in high purity indium by graphite furnace atomic absorption spectrometry after ion-exchange separation

The sample was dissolved in hydrochloric acid and separated with cation exchange resin. After the solution was concentrated by evaporation,trace lead in high purity indium was determined by graphite furnace atomic absorption spectrometry. The optimum conditions for sample dissolution,ion-exchange separation and determination of lead were investigated. It was indicated that 1 g of indium could be dissolved with 8 mL of hydrochloric acid. Trace silver,arsenic,cadmium,silicon and most of indium in the sample could be separated and removed after ion-exchange with 0.5 mol/L hydrochloric acid as leacheate. Then,lead could be eluted with 2.0 mol/L hydrochloric acid. Although aluminium,copper,iron,magnesium,nickel,tin,thallium,zinc and less than 10 μg indium could not be separated from lead,they had no influence on the determination. With sample dosage as 1 g,diluted volume as 1.0 mL and sample volume as 50 μL,the linear range of this method was 0.5-4.0 ng/mL,and the limit of quantitation was 0.000 6 μg/g,which was lower than that of industry standard method YS/T230.1-1994 (0.1 μg/g) by three orders of magnitude. The proposed method was applied to the analysis of actual sample,and the results were consistent with those obtained by inductively coupled plasma mass spectrometry (ICP-MS). The relative standard deviations (RSD,n=8)was 1.1%-19.7%,and the recoveries were 92%-120%.