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基于稀HCl介质中,在表面活性剂TritonX-100存在下,痕量钒(V)对重铬酸钾氧化偶氮胂Ⅲ(AsAⅢ)的褪色反应有明显的催化作用,建立了测定痕量钒(V)的动力学光度法。方法检出限为0.15μg/L,线性范围为0～20.0μg/L。在25mL溶液中,测定0.5μg钒(V)的相对标准偏差为3.23%(n=11)。讨论了酸度、反应物浓度、温度、反应时间、干扰离子等因素的影响。研究了反应的最佳条件,并测定了一些动力学参数,催化反应的表观活化能为30.21kJ/mol。结合溶剂萃取分离,实现了样品中痕量钒(V)的测定。方法用于人发、植物、茶叶样品中钒(V)的测定,结果与认定值相符;用于测定食品中的痕量钒(V),结果与原子吸收光谱法相符。相对标准偏差为1.18%～4.00%,标准加入回收率为97.5%～102.5%。
In the presence of surfactant TritonX-100, a trace amount of vanadium (V) catalyzed the oxidation of arsenazo Ⅲ (AsA Ⅲ) catalyzed by potassium dichromate in dilute HCl medium. A method for the determination of trace vanadium (V) Kinetic spectrophotometry. The detection limit was 0.15μg / L and the linear range was 0 ~ 20.0μg / L. The relative standard deviation of 0.5 μg vanadium (V) was determined to be 3.23% (n = 11) in 25 mL of solution. The effects of acidity, reactant concentration, temperature, reaction time, interfering ions and other factors were discussed. The optimum reaction conditions were studied and some kinetic parameters were determined. The apparent activation energy of the catalytic reaction was 30.21 kJ / mol. Combined with solvent extraction and separation, the determination of trace vanadium (V) in the sample was achieved. The method was applied to the determination of vanadium (V) in human hair, plants and tea samples. The results were consistent with the certified values. The method was applied to the determination of vanadium (V) in food samples. The results were in good agreement with atomic absorption spectrometry. The relative standard deviations were 1.18% ~ 4.00%, and the standard recoveries were 97.5% ~ 102.5%.