重铬酸钾氧化偶氮胂Ⅲ动力学光度法测定痕量硒(英文)

Catalytic Spectrophotometric Determination of Trace Vanadium Based on Oxidation of Arsenazo Ⅲ with Bichromate by Using Triton X-100 to Enhance Its Effect

基于稀HCl介质中,在非离子表面活性剂Triton X-100存在时,痕量钒(V)催化重铬酸钾氧化偶氮胂Ⅲ的褪色反应,建立了测定痕量钒(V)的催化动力学光度法。方法检出限为0．15μg/L,线性范围为0．0～20．0μg/L。结合离子交换树脂分离,实现了食品中痕量钒(V)的测定,加标回收率为97．5%～102．5%,样品测定的相对标准偏差(RSD)为1．18%～4．00%。用于测定人发、植物、茶叶样品中的痕量钒(V),结果满意。

A catalytic spectrophotometry for the determination of trace vanadium（V） based on its catalytic effect on discoloring reaction of oxidation of arsenazo Ⅲ （AsA Ⅲ） with potassium bichromate in a weak acid medium is described, and the addition of Triton X- 100 can further increase the sensitivity of the reaction and its catalytic extent is linear with the content of V（V）. The reaction rate is monitored spectrophotometrically by measuring the decrease in absorbance of AsA Ⅲ at 550 nm after a fixed time （8 min）. The calibration graph is linear in the range of 0.0-20.0μg/L vanadium （V） and the detection limit of the method is 0.15μg/L. Combined with ion-exchange resin separation. The method has been successfully applied to the determination of V（V） in food samples with the relative standard deviation of 1.18% -4.00% and the recovery of 97.5% - 102.5%. The results are in good agreement with those provided by AAS method. The method has also been applied to the determination of V（V） in human hair, plant and tea samples, and the results are in agreement with certified values.