巯基葡聚糖凝胶分离富集动力学光度法测定痕量锡

Catalytic-Kinetic-Photometric Determination of Trace Amounts of Tin After Enrichment with Mercapto-Dextran Gel

基于稀硫酸介质中,痕量锡（Ⅳ）催化溴酸钾氧化偶氮氯膦Ⅲ（CPAⅢ）的褪色反应,建立了测定痕量锡（Ⅳ）的催化动力学光度法。方法检出限为0.25μg·L^-1,线性范围为0.0～8.0μg·L^-1。结合巯基葡聚糖凝胶（MDG）分离富集,用于测定环境水样、人发及岩石样品中痕量锡（Ⅳ）,结果的RSD值均在9.0%以内,回收率在96.0%～103.0%之间。分析了3种岩石标准物质,所得结果与证书值相符。

It was observed that the oxidative color-fading reaction of CPA Ill with potassium bromate was catalyzed by the presence of trace amounts of Sn（Ⅳ） in dil. H2SO4 medium. Linear relationship between the magnitude of the decrease in absorbance intensity at 530 nm and the concentration of Sn（Ⅳ） was found in the range of 0. 0-8. 0 μg· L^-1 , with a detection limit 0. 25 μg · L^-1. Based on these facts, a photometric method for the determination of trace amounts of Sn（Ⅳ） was proposed. For enrichment of traces of Sn（Ⅳ） from some complex samples, separation by the adsorption of Sn（Ⅳ） on mercapto-dextran gel was used. The proposed method has been used in the determination of traces of Sn（Ⅳ） in sample of ores, river water and human hair, giving values of RSDts less than 9. 0%, and values of recovery in the range from 96. 0% to 103.0%. In the analysis of 3 CRM＇s of rocks, the results obtained were in consistency with the certified values.