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提出一种催化动力学光度法测定生物样品中草酸的方法。基于在硫酸介质中，草酸能有效地催化重铬酸钾氧化丁基罗丹明Ｂ褪色，当反应温度为６５℃、反应时间１２ ｍ ｉｎ时，非催化反应溶液的吸光度Ａ０ 和催化反应溶液吸光度Ａ 的ｌｎ Ａ０Ａ 值与草酸浓度在０．２０～１０．０８ μｇ／ｍ Ｌ之间存在良好线性关系。反应体系用高浓度ＮａＯＨ 终止后室温下可稳定２ ｈ 以上。催化反应的表观活化能为１３．５３ ｋＪ／ｍ ｏｌ。方法可直接用于菠菜、童尿、草莓晶等生物样品中草酸的测定。
A catalytic kinetic spectrophotometric method for the determination of oxalic acid in biological samples was proposed. Based on sulfuric acid medium, oxalic acid can effectively catalyze the oxidation of butyl rhodamine B by potassium dichromate. When the reaction temperature is 65 ℃ and the reaction time is 12 mins, the absorbance A0 of the non-catalytic reaction solution and the absorbance of the catalytic reaction solution A Ln A0A value and oxalic acid concentration between 0.20 ~ 10.08 μg / m L there is a good linear relationship. After the reaction system was terminated with high concentration of NaOH, it was stable at room temperature for more than 2 h. The apparent activation energy of the catalytic reaction is 13.53 kJ / mol. The method can be directly applied to the determination of oxalic acid in biological samples such as spinach, urine, strawberry crystal.