土壤中钼的比色测定

Colorimetric assay of Mo in soil

土壤中的钼,常伴有钨、锡、铜、铅、锌、银、铼、锰、铁、钒、铋等多金属,尤其是钨、铁、锰、铅对钼的测定带来干扰。本文采用碳酸钠-氧化锌熔融后硫氰酸盐比色法测定多金属矿石中钼。实验研究确定了各试剂最佳加入量,熔矿和显色的温度、时间,显色酸度和干扰消除等因素,提高了方法的灵敏度和稳定性。试样在0.00-500.00ug范围内均呈良好的线性,相对误差小于3%,方法相对标准偏差(RSD,n=9)值小于4.0%。实验采用平行样实验、国家一级标准物质重复实验、空白实验进行实验质量控制和验证。国家一级标准物质测定值与推荐值相符。该方法在实际生产中能准确、快速、大批量分析样品,满足了地质普查和实验测试工作的需要。

Mo is usually associated with W, Sn, Cu, Pb, Zn, Ag, Re, Mn, Fe, V and Bi in soil and its determination is interfered especially by W, Fe, Mn, Pb and Mo. This paper applied melted sodium carbonate-zinc oxide, sulforhodanite colorimetric method to determination of Mo in polymetallic ore. Test study determined the best addition of each reagent, temperature and time of ore melting and coloration, coloration acidity and interference elimination, etc., thus improving the sensitivity and stability of the method. Samples all gave well linear result in the range of 0.00-500.00ug, with relative error less than 3%, RSD below 4.0% （n=9）. The test was done on duplicate samples, repeatedly on state primary reference material, with blank test for quality control and verification. The measurement of state primary reference material was in conformity with recommended value. This method is accurate, fast in assay of samples in large quantities meeting the demand of geological general survey and test.