农产品中痕量钒的测定研究

目的]建立一种测定痕量钒（V）的新方法。方法]在柠檬酸介质中，利用KBrO，氧化柠檬黄褪色反应测定痕量钒。首先绘制吸收曲线，选择测定波长，然后研究反应的最佳条件包括柠檬酸用量、KBrO，溶液和柠檬黄溶液用量以及反应的温度与时间，确定线性范围及检出限，测定表观活化能，并研究共存离子的影响。结果]选择测定波长为430nm。在柠檬酸介质中，钒对KBrO，氧化柠檬黄具有强烈的催化作用。反应的最佳条件为柠檬酸用量3．5mg／L,KBrO3，溶液2．5ml，柠檬黄2．5mg／L，反应温度93℃。反应时间16min。测定痕量钒方法的线性范围为0～40μg／L，方法检出限为3．8rig／ml，RSD为2．36％。结论]采用该方法测定农产品中痕量钒具有灵敏度较高、抗干扰离子能力强、操作简便的特点。

Study on Determination of Trace Vanadium in Agricultural Products

Objective] The study aimed to establish a new method of determining the trace vanadium.Method] In the citric acid medium,the fading reaction with the KBrO_3 oxidation of citric yellow was used for the determination of trace vanadium.Firstly,the absorption curve was drawn to choose the measuring wavelength,and then,the optimal conditions including the dosages of citric acid,KBrO_3 solution and citric yellow solution and the reaction temperature and the time were studied.Tthe linear range and detection limit were confirmed,the apparent activation energy was determined,and the influence action of the coexistence ions was studied.Result] The measuring wavelength was selected as 430 nm.In the citric acid medium,the vanadium had strong the catalytic role in the KBrO_3 oxidation of citric yellow.The optimum conditions for the reaction was as follows: the citric acid dosage of 3.5 mg/L,KBrO_3 solution of 2.5 ml and citric yellow dosage of 2.5 mg/L,reaction temperature of 93 ℃ and reaction time of 16 min.The linear range for the method of determining the trace vanadium was 0-40 μg/L,with the detection limit of 3.8 ng/ml.and the RSD of 2.36%.Conclusion] Using the method of determining the trace vanadium had the characteristics of high sensitivity,strong anti-interference ion ability,simple and convenient operation.