| Popis: |
A rapid microdetermination of salicylic acid by coulometric titration using electrolytically generated bromine and cuprous ion was studied. A satisfactory result was found to be obtained with a simple constant current source and an amperometric indicator system.A potential difference of 250 mV was applied between the indicator electrodes immersed in the electrolyte composed of 0.3N hydrochloric acid, 0.1N copper sulfate, and 0.1N potassium bromide. Mearsurering the time of electrolysis at a constant current of 10mA, an excess of bromine was generated for completing reaction with salicylic acid. After standing for 2 minutes, the excess bromine was back-titrated electrolytically generated cuprous ion. The end point was obtained amperornetrically by observing the current flow between the indicator electrodes. From the number of coulombs of electricity required to generate bromine reacted with salicylic acid, 50-300ϒ of salicylic acid was determined within 5-7 minutes. |
