硫脲析出-自动光度滴定法测定钯化合物中钯

Determination of palladium in palladium compounds by thiourea release-automatic photometric titration

用硫脲选择性析出钯-EDTA中的钯,用自动光度滴定法滴定与钯等量的EDTA,实现钯化合物中含钯量的测定。对方法测定波长、硫脲用量、终点突跃ΔE值、共存离子影响重要条件,以及常规滴定条件进行了系统研究。结果表明,测定19%~60%钯含量,方法相对标准偏差(RSD,n=11)为0.11%~0.19%,加标回收率为99.64%~100.27%,测定结果与相关标准方法吻合。采用硫脲代替丁二肟,解决了丁二肟钯絮状沉淀包裹光度电极表面影响测定,以及采用自动光度滴定法有效解决钯棕红色影响目视终点准确判定的问题,实现钯含量的自动快速测定,提高工作效率。

After palladium in palladium-EDTA was selectively released by thiourea,EDTA equal to the amount of palladium was analyzed by using automatic photometric titration.In this way,the determination of palladium in palladium compounds was realized.The wavelength of determination,the amount of thiourea,the value of end-point jumpΔE,the influence of coexisting ions and the conventional titration conditions were studied systematically.The results showed that when the palladium content was in the range of 19%~60%,the relative standard deviation(RSD,n=11)was 0.11%~0.19%with a spiked recovery rate of 99.64%~100.27%,consistent with the related standard methods.Choosing thiourea instead of dimethylglyoxime as a releasing agent can solve the problem arising from the precipitation of dimethylglyoxime-Pd complex on the surface of the photometric electrode,and using automatic photometric titration can eliminate the error in judging the titration end point by the visual inspection.The automatic and rapid determination of palladium content can be realized by adopting the method developed in this study.