钒-5-Br-PADAP-溴酸钠体系极谱催化波的研究

Study on Polarographic Catalytic Wave in Vanadium- 2-[(5-Bromo-2-Pyridyl)-Azo]5-Diethylaminophenol-Sodium Bromate System

报道了钒在5-Br-PADAP-溴酸钠介质中极谱催化波的形成条件和反应机理。该法测定钒的线性范围为(0.04～20)×10^(-3)ppm,检测限可达0.02×10^(-3)ppm,较成功地应用于水样和矿样分析。

In a supporting electrolyte containing 4.0 × 10-6mol/L 5-Br-PADAP, 0.025mol/L NaBrO3, 0.002mol/L H2SO4,0.008mol/L Na2SO4(pH = 2.40?0.05), a sensitive polarographic catalytic wave of vanadium was obtained by using single-sweep polarography. The peak potential of this wave appears at -0.17V. The change of peak height of derivative wave with concentration of vanadium is linear in the range from 0.04 × 10-3ppm to 20 ×10-3ppm.The method has been successfully applied to the determination of vanadium in tap water and ores. The composition and the condition stability constant of the vanadium(V) complex with 5-Br-PADAP have been determined. The electrode processes of the catalytic wave may be presented as folios. [VO2-5-Br-PADAP]adS +2H+e→[VO-5-Br-PADAP]ads +H2OBrOI