抗坏血酸活化溴酸钾氧化番红花红O催化荧光法测定痕量钒(Ⅴ)

Determination of trace vanadium (V) by Fluorescence Spectrophotometry based on the catalyzed reaction of potassium bromate oxidizing safranine O activated by Vitamin C

基于在硫酸介质和十二烷基苯磺酸钠(DBS)存在下，抗坏血酸(Vc)活化钒(V)催化溴酸钾氧化番红花红O(R)发射强而稳定的荧光的特性，建立了Vc活化溴酸钾氧化番红花红O催化荧光法测定痕量钒(V)的新方法。该催化反应呈一级反应，动力学参数速率常数k=7．3×10^-4／s，表观活化能E=46．09kJ／mol。当加维生素C时△If提高10倍。V(V)含量在0．040—40．0Pg／mL范围内与△If符合比尔定律。工作曲线的回归方程△If=116．2+3．932Cv(v)、(pg/mL)，n=6，相关系数r=0．9991。检出限为3．3×10^-13／mL。该方法快速、简单、灵敏、重现性好，成功用于茶叶和人发中痕量钒的测定。同时探讨了催化反应机理。

A new method for the determination of trace vanadium (V) by fluorescence spectrophotometry has been established. It is based on the facts that in the presence of sulfuric acid and sodium dodecyl benzene sulfonate (DBS), vanadium activated by vitamin C (Vc) can catalyze potassium bromate to oxidize safranine O (R), the oxidation products of safranine O can emit intense and stable fluorescence on nitrocellulose membrane. The catalytic reaction is a first order reaction, with a reaction rate constant (k) of 7.3?04 s1, and the apparent activation energy (E) is 46.09 KJ/mol. The flourescence intensity (腎f) will be increased 10 times if vitamin C is added. The linear range of this method is 10.040 ~ 40.0 pg /m L within which △If obeyed Beers Law, the detection limit (LD) is 3.310-13/mL, and the regression equation for working curve is △If = 116.2+3.932 C V(Ⅴ) (pg/mL), n = 6, correlation coefficient r is 0.9991. This sensitive method has been applied to the determination of trace vanadium in tea and human hair samples successfully. The mechanism of the catalytic reaction was also discussed.