钒试剂亚硝化的示波极谱法研究及其测定

Study on the Nitrosation and Determination of 2-(Phenylamho)-Benzoic Acid by Linear-Sweep Voltammetry

本文报道一种测定钒试剂的单扫描示波极谱法,它是基于在较浓的乙酸介质中钒试剂与亚硝酸盐作用迅速亚硝化,然后用极谱法对其亚硝化产物进行定量测定。本文研究了钒试剂亚硝化和测定的条件。实验表明,在4%乙酸-0.12mol/1.H_2SO_4 4×10^(-5)(4.8×10^(-4)、1.2×10^(-3))mol/L NaNO_2底液中,钒试剂亚硝化产物的极谱还原波波高与钒试剂浓度在4.0×10^(-7)mol/L～1.2×10^(-4)mol/L范围内有良好的线性关系,检测下限为1×10^(-7)mol/L。合成钒试剂的原料杂质如邻氯苯甲酸、苯胺和Cu^(2-)、Ni^(2+)、Zn^(2+)等不干扰测定。

A method for the determination of 2-(phenylamino)-benzoic acid(Ⅰ) is developed by linear-sweep voltammetry. The method is based on a quick nitrosation of I by nitrite in concentrated HAc medium and subsequent polarographic evaluation of the nitrosation product N-nitroso-I(Ⅱ). The conditions of the nitrosation and the determination of I are studied. The resuits show that the peak height of Ⅱ is proportional to the concentration of I in the range from 4×10^(-7)mol/L to 1.2×10^(-4)moI/L in 4% HAc-0.12mol/L H_2SO_4-4× 10^(-5)(4.8×10^(-4),1.2×10^(-3))mol/L NaNO_2 supporting electrolyte, The detection limit is 1×10^(-7)mol/L. o-Chloro-benzoic acid, phenylamine as impurities from raw materials to synthesize I and Cu, Ni, Zn ions do not interfere.