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前文已报道改进的界面电化学池测定生物碱。对于有机化合物中羧基的半微量测定过去常于非水介质中,以玻璃电极或锑电极为指示电极,以饱和甘汞电极或玻璃电极为参比电极进行电位滴定。药典对于药物制品中羧基的测定沿用容量分析法。本文首次应用改进的界面电化学池作为非水介质及水介质中酸碱电位滴定的终点指示器,对含有羧基的二十八种有机酸的测定其回收率为98.04～101.90％。对五种有机酸性药物及片剂进行测定,其结果与药典法基本符合。该法具有分析快速,操作简便,结果准确,终点突跃,样品用量微克级或毫克级,以及仪器简单价廉的优点。方法对于测量有机酸(特别是一些从天然植物中得到的微量有机酸)和有机酸性药物是优越的,在天然物化学及生物化学的研究中具有实用价值。
The foregoing has been reported to improve the electrochemical interface of the electrochemical cell for the determination of alkaloids. For organic compounds in the semi-trace determination of carboxyl in the past often in non-aqueous media, the glass electrode or antimony electrode as the indicator electrode, saturated calomel electrode or glass electrode as the reference electrode for potential titration. Pharmacopoea for the determination of carboxyl in pharmaceutical products used in volume analysis. In this paper, for the first time, an improved interface electrochemical cell was used as the endpoint indicator of acid-base potentiometric titration in non-aqueous media and aqueous media. The recovery of twenty-eight organic acids containing carboxyl groups was 98.04% -101.90%. The five kinds of organic acid drugs and tablets were measured, the results are consistent with the pharmacopoeia. The method has the advantages of fast analysis, simple operation, accurate results, sudden end point, microgram level or milligram amount of sample, and the advantages of simple and inexpensive instruments. The method is superior for the measurement of organic acids (especially trace organic acids derived from natural plants) and organic acid drugs, and has practical value in the study of natural chemical and biological chemistry.