催化光度法直接测定痕量水杨酸

Direct Determination of Trace Salicylic Acid by Catalytic Photometry

本文研究了水杨酸在硫酸环境中减弱了碘对亚砷酸与硫酸铈氧化还原反应的催化作用及其动力学条件，建立了动力学的直接光度法测定痕量水杨酸的新方法。结果表明，在0．001mol／LCe（SO4）2，0．00125mol／LAs2O3，0．01mg／LKI，0．225mol／LH2SO4和0．13％NaCl介质溶液中测定水杨酸，其表现摩尔吸光系数为8．3×104L·mol-1·cm－1；线性范围为0．01～0．75mg／L。用本法对样品复方苯甲酸醇溶液中水杨酸的测定，结果满意。

In this paper the reduction and kinetic conditions of iodide anion catalyzed oxidation of arsenous acid with cerium (Ⅳ ) sulfate in the presence of salicylic acid and sulfuric acid were studied. Based on this technique a new catalytic photometric method for the determination of trace salicylic acid was established. It is shown that the apparent molar absorptivity and linear range are 8. 3 ×104 L. mol-1· cm- 1 and 0. 01～0. 75 mg/L respectively for the determination of salicylic acid in solution containing 0. 001 mol/L Ce (SO4)2 0. 00125 mol/L As2O3, 0. 01 mg/L KI, 0. 225 mol/L H2SO4 and 0. 13%NaCl. This method has been used to determine salicylic acid in ethanol solution of compound benzoic acid with satisfactory results.