钼(Ⅵ)和钼(Ⅴ)与硫氰酸盐及维多利亚蓝4R在水溶液中显色反应及其应用

Colour Reactions of Molybdenum(Ⅵ)and Molybdenum(Ⅴ) with Thiocyanate and Victoria Blue 4R in Aqueous Solution and Their Application

基于钼(Ⅵ)和钼(Ⅴ)与硫氰酸盐和维多利亚蓝4R在增溶剂存在的水溶液中的显色反应,发展了一种高灵敏分光光度测定钼的方法。显色反应的适宜酸度是:钼(Ⅵ)0.02～0.08M硫酸溶液,钼(Ⅴ)0.48～0.72M硫酸溶液。离子缔合物的组成:钼(Ⅵ)是(VB4R)_4·〔MoO_2(SCN)_5),钼(Ⅴ)是(VB4R)2·〔MoO(SCN)_5〕。两种离子缔合物最大吸收波长均位于575nm处,摩尔吸光系数分别为2.64×10~5 〔钼(Ⅵ)〕和1.30×10~5〔钼(Ⅴ)〕。钼(Ⅴ)的离子缔合配合物比钼(Ⅵ)的离子缔合配合物具有更高的选择性,可以用于直接分光光度法测定钢铁中微量钼。

The highly sensitive spectrophotometric methods have been developed for the determination of molybdenum/based on the colour reactions of Mo(Ⅵ)and Mo (Ⅴ)with thiocyanate and victoria blue 4R in aqueous solution in the presence of some surfactants. The composition of the formed ionassociates are (VB4R) 4 [MoO2(SCN)3 in 0.02-0.08M sulfuric acid solution for Mo (VI) and (VB4R)2 [MoO (SCN)5]in 0.48-0.72M sulfuric acid solution for Mo (Ⅴ) . The wavelenths of maximum absorbance for both the ion associates are at 575 nm and their molar absorptivities are 2.64X105 for Mo (Ⅵ) complex),1.30×106 for Mo(Ⅴ),respectively. The Mo (Ⅴ) ion association complex has higher selectivity than Mo (Ⅵ) ion association complex and can be applied to direct spectrophotometric determination of micro-amouns of moly.denum in iron and steel.