钒-络蓝黑R络合物在碳糊电极上的阳极吸附伏安法研究及痕量钒的测定

ANODIC ADSORPTIVE VOLTAMMETRIC DETERMINATION OF TRACE AMOUNTS OF VANADIUM BY THE REACTION OF VANADIUM(Ⅴ)-ERIOCHROME BLUE BLACK R COMPLEXAT CARBON PASTE ELECTRODE

研究了钒-络蓝黑R(EBBR)络合物在碳糊电极上的吸附伏安行为。在pH4.7的0.2mol.L-1HOAc-NaOAc缓冲溶液,于0.4V富集,从0.4~1.4V以300mV.s-1的速率线性扫描。在1.17V(vs.SCE)的二次导数氧化峰电流与钒的浓度在9.0×10-10~6.0×10-8mol.L-1(1.2×10-6mol.L-1EBBR)和6.0×10-8~6×10-7mol.L-1(3.0×10-6mol.L-1EBBR)范围内呈线性关系,富集450s,检出限为4.0×10-10mol.L-1(S/N=3)。该法用于花生仁和自来水样中钒的测定,结果满意。

A new method for the determination of vanadium based on anodic adsorptive voltammetry of the vanadium ()-Eriochrome blue black R(EBBR) complex at carbon paste electrode (CPE) was presented. Optimum analytical conditions were found to be: 0.2 molL^(-1) HOAc-0.2 molL^(-1) NaOAc (pH 4.7), enriched at 0.4 V for 420 s and scanned at rate of 300 mVs^(-1). The vanadium ()-EBBR complex was adsorbed on the surface of the CPE and an anodic peak at 1.17 V (vs.SCE) produced. The linear concentration range for vanadium () is 9.010^(-10)6.010^(-8)molL^(-1) (1.210^(-6)molL^(-1) EBBR) and 6.010^(-8)6.010^(-7)molL^(-1) (3.010^(-6)molL^(-1) EBBR). The detection limit is as low as 4.010^(-10)molL^(-1) (S/N=3) for enrichment for 450 s. The proposed method has been applied successfully to the determination of vanadium in samples of peanut and tap water.