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Coulometric determination of organic acids

1962; Wiley; Volume: 39; Issue: 11 Linguagem: Inglês

10.1007/bf02637227

1558-9331

R. O. Crisler, Ralph D. Conlon,

Electrochemical Analysis and Applications

Abstract A system has been devised for the coulometric titration of organic acids in a non‐aqueous medium. The solvent system is benzene‐methanol, 1蝘1, containing LiCl as the electrolyte. The acid is titrated by reducing hydrogen ion at a platinum cathode. The anode reaction involves the formation of AgCl on silver. The endpoint is detected by an antimony‐glass electrode pair and the derivative of the electrode output is used to effect automatic current shut‐off. Alternative reference electrodes are discussed. Usual sample size titrated is 0.01 meq but the method can be applied to both larger and smaller amounts. The method has been applied to the determination of acid value and free fatty acid in fatty materials. The advantages of the coulometric determination are: 1) No standard solutions are required. 2) The titration is conducted without analyst attention. 3) The technique is simple and rapid.