火试金-电感耦合等离子体原子发射光谱法测定提钯螯合剂中残余钯

Determination of residual palladium in palladium chelating agent by inductively coupled plasma atomic emission spectrometry after fire assaying

一种新型提钯螯合剂可富集溶液中微量钯,而提钯后的螯合剂中还残余钯,其存在形式比较复杂,酸溶法不易完全将钯溶解。采用火试金法对提钯螯合剂富钯提钯渣进行前处理,使其中残余钯富集在银合粒中,再使用硝酸和盐酸溶解合粒,选择Pd 340.458nm为分析线,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定钯,从而建立了提钯螯合剂中残余钯的测定方法。试验讨论了熔融时银加入量、测钯时不同酸介质和酸度、银合粒酸溶后沉淀时间对钯测定结果的影响。结果表明:当熔融时加入银量在钯量的3倍以上,测定介质为10%王水,沉淀时间为4h或者放置过夜,钯测定结果更准确;钯在1~15μg/mL范围内校准曲线呈线性,线性相关系数为0.999 998;方法检出限为0.019μg/mL。按照实验方法测定4个提钯螯合剂中残余钯,结果的相对标准偏差(RSD,n=12)为0.46%~0.62%,加标回收率为99%~102%。

A novel palladium chelating agent can enrich trace palladium in solution.There is residual palladium in chelating agent after the extraction of palladium with very complex existing form,which cannot be completely dissolved in acid.The palladium-rich chelating agent residue was pretreated by fire assaying method.The residual palladium was enriched in silver granules.Then,the silver granules were dissolved with nitric acid and hydrochloric acid.Pd 340.458 nm was selected as the analytical line.The content of palladium was determined by inductively coupled plasma atomic emission spectrometry（ICP-AES）.Thus the determination method of residual palladium in palladium chelating agent was established.The effect of silver amount added in the melting process,the acid medium and acidity during the determination of palladium and the precipitation time after acid dissolution of silver granules on the determination results of palladium content was investigated.The results showed that the determination of palladium content was accurate under the following conditions：the amount of silver added in melting was more than 3 times of palladium amount,the determination medium was 10% aqua regia,and the precipitation time was 4 hor overnight.The calibration curve of palladium was linear when the content of palladium was in the range of 1-15μg/mL,and the correlation coefficient was 0.999 998.The detection limit was 0.019μg/mL.The residual palladium in 4 palladium chelating agents was determined according to the experimental method.The relative standard deviations（RSD,n=12）of determination results ranged from 0.46% to 0.62%.The recoveries were between 99% and 102%.