论文部分内容阅读
建立了KSCN自动电位滴定法测定锡铅焊料中Ag的方法。富锡或铅焊料试样以HNO3-酒石酸-Na2EDTA混合试剂分解与络合,可使其溶解完全并能抑制Sn水解沉淀,Fe(Ⅲ)用抗坏血酸还原,在1.6 mol/L HNO3-聚乙烯醇(20 g/L)-水介质中,以银电极作指示电极,用0.02 mol/L KSCN标准溶液动态滴定Ag含量。对仪器滴定参数、试样分解、滴定时酸度、试剂用量、测定范围、等当点重现性、共存元素影响等分析条件进行了实验优化。Ag量在3.0~50.0 mg范围内与其耗用KSCN标准滴定溶液体积呈线性关系,相关系数为0.99999,方法的检出限(3s/k)为6.8μg。方法用于代表样及标样中0.513%~5.01%Ag的测定,RSD(n=11)为0.42%~1.7%,回收率为98.8%~103%,标样测定值与标准值相吻合。
A KSCN automatic potentiometric titration method for the determination of Ag in tin-lead solder was established. The samples of tin-rich or lead-solder were decomposed and complexed with HNO3-tartaric acid-Na2EDTA mixed reagent to dissolve completely and inhibit the precipitation of Sn. Fe (Ⅲ) was reduced with ascorbic acid in 1.6 mol / L HNO3- (20 g / L) - aqueous medium with silver electrode as the indicator electrode, with 0.02 mol / L KSCN standard solution titration of Ag content. The experimental optimization was carried out on the instrument titration parameters, sample decomposition, titration acidity, reagent dosage, determination range, equivalent point reproducibility, coexistence of elements and other analysis conditions. The amount of Ag in the range of 3.0-50.0 mg was linear with the volume of KSCN standard titration solution. The correlation coefficient was 0.99999. The detection limit (3s / k) of the method was 6.8 μg. The method was applied to the determination of 0.513% ~ 5.01% Ag in representative samples and standard samples. The RSD (n = 11) was 0.42% ~ 1.7% and the recovery was 98.8% ~ 103%.