COULOMETRIC DETERMINATION OF PHENOLS USING SELF ASSEMBLED COULOMETER

Abstract

Coulometry is a technique in analytical chemistry that determines the amount of matter transformed during an electrolysis reaction by measuring the amount of electricity (in coulombs) consumed or produced. A coulometer was assembled in-house. The coulometer was calibrated using iodine-thiosulphate reaction: thus, generated iodine from 10% KI solution with sensitivity of 1.761×10-4molmin-1 and from 2% KI solution with sensitivity of 5.162×10-7molmin-1. The coulometer was applied to determine the relative molar masses of sodium thiosulphate, phenols, acetylsalicylic acid, ascorbic acid. The values obtained are in agreement with technical report they are 242.4±1gmol-1, 93.35±0.17gmol-1, 136.0±0.3gmol-1 and 171.6±0.5gmol-1 respectively. The activity of phenol and substituted phenols of Izal was checked coulometrically. The coulometer was applied to the ascorbic acid content of titration of lime juice and the phenolic components of the cashew nut shell liquid (CNSL). The technical molar mass obtained for the phenolic components of CNSL is 5024.0±38.08gmol-1 A thermal glycerol extraction method developed for CNSL offered an efficiency of which the assembled extractor ramped at 0.820Cs-1 and 0.720Cs-1 yielding initiation yield of 20% CNSL.