【摘要】 对钴与４－［（５－氯－２－吡啶）偶氮］－１，３－二氨基苯（５－Ｃｌ－ＰＡＤＡＢ）形成络合物的吸收光谱进行探讨，结果表明：试剂及络合物在不同酸度条件下形成不同型体。在酸性条件下，络合物为大阳离子，钴离子以三价形式存在，钻与试剂的络合比为１：２。在强酸性介质中，将此络合物用于光度测定钻，方法选择性及稳定性好，且灵敏度极高。对水、粮食、土壤、茶叶及维生素Ｂ＿（１２）中微量钻进行直接测定，获得满意结果。更多还原

【Abstract】 The dissociation equilibrium of 4-（5-chloro- 2-pyridylazo）-1,3-diaminobenzene(5-Cl-PADAB andthe reaction mechanism with cobalt were studied byspectrophotometry. The resuLts showed that Co（Ⅲ）and the reagent form a cation complex with the ratioof 1: 2.Two absorbing species existing in acidic solu-tion were determined by using principal componentanalysis to th6data set of absorbances measured atdifferent pH and the reaction mechanism was suggest-ed. The reaction was investigated for applying to thedirect spectrophotometric determination of cobalt invarious materials such as environmental samples,food and vitamin B₁₂ etc. without separation。更多还原