以超级微波消解-全自动重金属分析联用系统测定土壤中18种元素(锂、铍、钒、铬、锰、钴、镍、铜、锌、砷、钼、银、镉、锑、铊、铅、铋、铀)的含量。取0.1 g土壤于消解管中,将消解管加载至上述联用系统,按照以下步骤自动完成加酸、消解、稀释、测定:加入1 mL水润湿样品,再加入1.5 mL硝酸、0.5 mL盐酸和0.5 mL氢氟酸,并程序升温至260℃,保温30 min;冷却、泄压、用水稀释后,用电感耦合等离子体质谱法测定。结果表明:18种目标元素的质量浓度均在一定范围内与其对应的信号强度与内标元素铑信号强度的比值呈线性关系,检出限(3s)为0.001~0.300 μg·L^-1;方法用于土壤成分分析标准物质GSS-2、GSS-13和GSS-27的分析,测定值均在认定值的不确定度范围内,其相对标准偏差(n=6)为1.3%~5.3%。方法消解用酸量仅为HJ 803-2016的50%,且自动化程度高、分析快速,适用于大批量土壤样品的分析。

A combined system of super microwave digestion and automatic heavy metal analysis was applied to determination of 18 elements (Li, Be, V, Cr, Mn, Co, Ni, Cu, Zn, As, Mo, Ag, Cd, Sb, Tl, Pb, Bi, U) in soil. The soil of 0.1 g was taken and loaded on the above combined system to automatically complete acid addition, digestion, dilution and determination as the following steps:1 mL of water was added to wet the sample, then 1.5 mL of nitric acid, 0.5 mL of hydrochloric acid, and 0.5 mL of hydrofluoric acid were added, and the mixture was heated to 260℃ by program temperature and kept for 30 min; after cooling, depressurization, and dilution with water, inductively coupled plasma mass spectrometry was used for determination. It was shown by the results, the mass concentrations of 18 target elements were linearly related to their corresponding signal intensity ratios between target element and internal standard element of Rh in definite ranges, with detection limits (3s) in the range of 0.001-0.300 μg·L^-1; the proposed method was used for the analysis of standard substances for soil composition analysis (GSS-2, GSS-13 and GSS-27), and the determined values were in the uncertainty ranges of the certified values, with RSDs (n=6) of the determined values in the range of 1.3%-5.3%. The amount of acid used for digestion was only 50% of that of HJ 803-2016, and the method had a high degree of automation and rapid analysis, which was suitable for the analysis of large batches of soil samples.