提出了氩气在线稀释-电感耦合等离子体质谱法(ICP-MS)测定土壤中镍、砷、钼、镉、锑、镨、钐、铕、铅、铀等10种痕量元素的方法。称取0.2 g烘干后的土壤样品置于烧杯中,加入15 mL硝酸、5 mL氢氟酸和5 mL盐酸,盖上表面皿,于180 ℃进行消解,待样品消解完全后,加入2~3 mL高氯酸,于150 ℃开盖赶酸至消解液近干或呈湿盐状,最后加入2 mL硝酸溶解。如果有剩余残渣,可视消解情况加入适量硝酸、氢氟酸和高氯酸重复消解,直至样品消解完全。所得溶液转移至离心管中,用水冲洗烧杯至少3次,冲洗液一并收集于离心管中,用水定容至25 mL。采用氩气在线稀释模式,设置雾化气流量为0.602 L·min^-1,稀释气流量为0.610 L·min^-1。结果表明:10种元素质量浓度在一定范围内与对应响应值和内标响应值的比值呈线性关系,检出限(3s)为0.000 6~0.12 μg·L^-1;对土壤成分分析标准物质GBW 07456进行准确度和精密度试验,各元素测定值均在认定值的不确定范围内,测定值的相对标准偏差(n=6)均小于4.0%。

A method for the determination of 10 trace elements, including nickel, arsenic, molybdenum, cadmium, antimony, praseodymium, samarium, europium, lead and uranium, in soil by inductively coupled plasma mass spectrometry (ICP-MS) with argon online dilution was proposed. The dried soil sample (0.2 g) was placed into a beaker, and 15 mL of nitric acid, 5 mL of hydrofluoric acid and 5 mL of hydrochloric acid were added, and the mixture covered surface dish was digested at 180 ℃. After the sample was completely digested, 2-3 mL of perchloric acid was added, and the digestion solution was open at 150 ℃ for driving acid to dry or wet salt state, finally 2 mL of nitric acid was added to dissolve it. If residue was remained, appropriate amounts of nitric acid, hydrofluoric acid and perchloric acid were used for repeated digestion according to the digestion condition until the sample was completely digested. The obtained solution was transferred into a centrifuge tube, and the beaker was rinsed with water at least 3 times. The rinsing solution was collected in the above centrifuge tube, and its volume was made up to 25 mL with water. Argon online dilution mode was used, and flow rates of atomized gas and diluted gas were set at 0.602, 0.610 L·min^-1, respectively. As shown by the results, linear relationships between the mass concentrations of 10 elements and response value ratios of analytes to internal standards were found in definite ranges, with detection limits (3s) in the range of 0.000 6-0.12 μg·L^-1. Tests for accuracy and precision were made on the reference material for soil composition analysis (GBW 07456), and the determined value of each element was within the uncertainty range of the certified value, and RSDs (n=6) of the determined values were less than 4.0%.