极谱法测定化探样品中钨钼的技术改进

Technical Improvement on Determination of Tungsten and Molybdenum in Geochemical Samples by Polarographic

针对传统极谱法测定化探样品中钨钼时操作手段繁琐问题加以改进。试样以硫酸-二苯乙醇酸-二苯胍-氯酸钠体系为混合底液,将经过碱熔融后的样品以甲基橙为指示剂,用硫酸(1+1)调酸度后,加入固定比例的混合底液,摇匀,无需定容,放置25~30min后直接测定。采用二次倒数波测定,钨峰电位在-660mV左右,钼峰电位在-30mV左右,钨钼的质量浓度在0.02~1.0μg/mL内呈线性关系,钨检出限为0.5μg/g,钼检出限为0.3μg/g。方法灵敏度高,快捷、简单,适用于大批量化探样品的测定。

In this paper,the complexity of the traditional polarographic method for the determination of tungsten and molybdenum in geochemical samples was improved.The sample was made of sodium sulphate-two benzilic acid-sodium chlorate system as a mixed substrate.Afterwards,the sample was melted with methyl orange as an indicator,then with sulfuric acid（1＋1）to adjust the acidity.A fixed proportion of mixed liquor was added,shacked well,and without a constant volume,directly measured after 25—30 minutes.Using two reciprocal waves,the tungsten peak potential was about-660 mV,the molybdenum peak potential was about -30 mV,the mass concentration of tungsten and molybdenum was linear in the 0.02—1.0μg/mL range,and the detection limit of tungsten was 0.5μg/g,and for molybdenum was 0.3μg/g.This method is highly sensitive,fast,simple,and is suitable for the determination of large quantities of geochemical samples.