2-(5-羧基-1,3,4-三氮唑偶氮)-5-二乙氨基苯酚-溴酸钾催化动力学光度法测定痕量钒

Catalytic kinetic spectrophotometric determination of trace vanadium(Ⅴ) with 2-(5-carboxy-1,3,4-triazolylazo)-5-diethylamino phenol and potassium bromate

研究了钒（Ⅴ）催化KBrO3氧化2-（5-羧基-1,3,4-三氮唑偶氮）-5-二乙氨基苯酚（CTZAPN）的退色反应及其动力学条件,退色反应程度与钒（Ⅴ）量在一定范围内呈线性关系,建立了测定痕量钒（Ⅴ）的催化动力学光度法。在H2SO4介质中,退色体系的最大吸收波长455 nm,钒（Ⅴ）的质量浓度在0.004~0.04μg/mL范围内符合线性关系,回归方程为ΔA=14.265 2ρ＋0.002 07（ρ：μg/mL）,相关系数r=0.998 7,体系的表观摩尔吸光系数为ε=7.30×105L.mol-1.cm-1,检出限为2.99×10-10g/mL。方法不经分离直接测定面粉和花生样品中的痕量钒,测定结果与AAS法的测定值相符。

A new catalytic kinetic spectrophotometry for the determination of trace vanadium was established based on the catalytic action of V（Ⅴ） on the oxidative fading reaction between 2-（5-carboxy-1,3,4-triazoleazo）-5-diethylamino phenol（CTZAPN） and KBrO3 in a medium of H2SO4 and under heating conditions.The maximum absorbance was detected at 455 nm.The calibration curve was linear in the range of 0.004～0.04 mg/L for V（Ⅴ）,and the linear regression equation was ΔA=14.265 2ρ＋0.002 07（ρ：μg/mL） with the correlation coefficient equating to 0.998 7.The detection limit and apparent molar absorptivity were 2.99×10-10 g/mL and 7.30×105 L·mol-1·cm-1 for V（Ⅴ）,respectively.The method was applied to the determination of trace vanadium in flour and peanut samples.The results were in good agreement with the values obtained by atomic absorption spectrometry.