钼合金焊料中钼的选择性测定

Selective Determination of Molybdenum in Molybdenum Alloy Solders

建立了盐酸羟胺还原Mo(Ⅵ),形成盐酸羟胺-Mo(Ⅴ)-EDTA络合物,锌盐滴定选择性测定钼含量的方法,重点研究了提高方法选择性的途径及其条件。结果表明:采用EDTA和专属性试剂,并结合相应的滴定方法,20余种金属离子不干扰测定;于0.01～0.05 mol/L HCl介质中,盐酸羟胺-Mo(Ⅴ)-EDTA络合物稳定,滴定终点敏锐;测定5.00～20.00 mg Mo,相对误差在-0.40%～+0.50%,测定3 x%～6 x%的Mo含量,相对标准偏差为0.064%～0.130%,样品加标准回收率在99.40%～100.60%;方法准确度和精密度高、选择性好、分析快速、操作简便和适用性强,已用于CoMo38、MoRu41和MoRuNi15.5-15.5合金焊料中Mo含量的测定,结果满意。

A method for selective determination of molybdenum content by hydroxylamine hydrochloride deoxidization molybdenum（ Ⅵ ） and form complex of hydroxylamine hydrochloride -molybdenum（ Ⅴ ） - EDTA, using zinc salt titration was proposed. The conditions and approaches for improving selectivity of the method were also dominant studied. The results indicated that more than 20 kinds of ions do not interfere in the determination using EDTA and special property reagents and corresponding titration method; the hydroxylamine hydrochloride - molybdenum（ Ⅴ ） - EDTA complex is stabile and titration end - point is sensitive at the medium of 0.01 -0.05 mol/L HCl; the relative error, relative standard deviation and recovery of adding standard molybdenum in samples are - 0.40% ＋ 0.50% for determination of 5.00 - 20.00 mg molybdenum, 0.064% - 0. 130% for molybdenum content from 3 x% to 6x% and 99.40% 100.60%, respectively. The proposed method has advantages of high accuracy and precision, good selectivity, rapid analysis, convenient operation, better applicability and it has applied to determination of molybdenum in CoMo38, MoRu41 and MoRuNil1.5-15.5 alloy solders with satisfactory results.