钛铁试剂褪色分光光度法测定药物中的抗坏血酸

Determination of Ascorbic Acid by Tiron Fading Spectrophotometric Method

在 p H=2 .1～ 3.3范围内 ,Fe3 + 氧化抗坏血酸 ,剩余 Fe3 + 与钛铁试剂形成绿色配合物 ,其最大吸收波长在 660 nm,建立了褪色分光光度法测定药物中抗坏血酸的新方法。抗坏血酸质量浓度在0～ 40 mg/L内服从比耳定律 ,其回归方程为 A=0 .0 2 2 2 7ρ- 0 .0 0 4 ,相关系数 γ为 0 .9990 ,用于药物中抗坏血酸的测定 。

Ascorbic acid was determined by Tiron fading spectrophotometric method using iron(III) as the oxidizer of ascorbic acid, and Tiron as the color metric reagent for iron(III) in the pH range of 2.1 to 3.3. The green complex exhibited the absorption peak at 660 nm where the Beers law was obeyed in the ascorbic acid concentration range of 0-40 mg/L with the equation A =0.022 27 ρ -0.004 and its relative coefficient γ 0.999 0. The proposed new method was applied to the determination of ascorbic acid in medicine with satisfactory results.