土壤中微量钒的分光光度测定方法研究——1-(2-吡啶偶氮)-2-萘酚-过氧化氢-十二烷基苯磺酸钠法

Photomtric determination of trace amounts of vanadium in soil by the color reaction with 1-(2-pyridylazo)-2-naphthol sensitized reagent

对钒(V)和1-(2-吡啶偶氮)-2-萘酚(PAN)-过氧化氢-十二烷基苯磺酸钠(SDBS)显色反应进行了试验,结果表明:在1 mol.L-1盐酸介质中,在SDBS存在下,钒与1-(2-吡啶偶氮)-萘酚和过氧化氢生成红色的多元络合物,络合物最大吸收波长为575 nm,表观摩尔吸收率为3.64×104L.mol-1.cm-1,钒的浓度在0.2～1.2μg.mL-1内符合比耳定律。络合物的组成比为n钒∶nPAN∶n过氧化氢=1∶1∶1。该方法用于土壤中钒的测定,测定值的相对偏差(n=20)均小于6%,回收率为100.4%～105.6%。

Abstract： The color reaction conditions of vanadium with 1- （2-pyridylazo） -2-naphthol （PAN） were researched, and a new method was developed for the determination of vanadium in soil. It was based on the fact that vanadium forms a stable complex with PAN and hydrogen peroxide in an acidic medium of 1 tool · L -1 HC1 and in the presence of sodium dodecyl- benzene sulfonate （SDBS） as sensitization agent. The maximum absorption of the complex was 575 nm with apparent molar absorptivity of 3.64 × 104 L · mol^-1 · cm^-1 The linear range of the method was 0. 2 - 1.2 μg·mL^-1. Beer＇s law was kept in the concentration range within 1.2 μg·mL^-1 of vanadium. The proposed method was used for determination of va- nadium in 4 samples of soil. The recoveris of vanadium in different levels were 100.4% - 105.6%. With RSD of no more than 6%.