贵金属冶金物料中微量钯、铂、铑的双波长分光光度法同时测定的研究

本文提出了用二苄基二硫代乙二酰胺（ＤｂＤＯ）为显色剂分光光度测定铑的方法，并进一步研究了该试剂与钯、铂的反应，从而建立了可在一个试样中同时测定该三元素的方法。在２～３ｍｏｌ／ＬＨＣ１溶液中，钯与ＤｂＤＯ在室温显色，用氯仿萃取并用８．４ｍｏｌ／ＬＨＣ１振荡有机相，然后在４５４ｎｍ测定。在萃余液中加入ＳｎＣｌ＿２，并在沸水浴中加热，使铂、铑的ＤｂＤＯ络合物生成，再用氯仿萃取，８．４ｍｏｌ／ＬＨＣ１振荡有机相，以双波长分光光度法同时测定。其中铂用双波长系数倍率法（λ′＿２＝５２１ｎｍ，λ′＿１＝５００ｎｍ，Ｋ＝２．５６３），铑用双波长等吸收波长法（λ＿２＝４００ｎｍ，λ＿１＝５４６ｎｍ）。铂和铑的含量为１：５或５：１时互不干扰。

Dual-Wavelength Spectrophotometric Method forDetermination of Trace Palladium,Platinum and Rhod-ium in Metallurgical Materials

A spectrophotometric method for the determinationof rhodium has been presented using dibenzyldithio-oxam-ide(DbDO)as reagent and the reaction of this reagentwith palladium and platinum was further investigated.Palladium, platinum and rhedium can be determined inthe same sample. Pd-DbCO comolex is formed at roomtemperature and measured at 454nm after being extractedinto cmoroform.Pt-DbDO and Rh-DbDo complexes areformed in the raffinate by heating on a water bath in thepresence of SnCl_2 and extracted with chloroform. Dual-wavelength spectrophotometric method is used for the de-termination of platinurn and rhodium, the measuringwavelength and reference wavelength being 521nm and500nm(K=2.563) for Pt,400nm and 546nm for Rh.Satisfactory results can be obtained with the ratio of plat-inum to rhedium from 5:1 to 1:5.