Modification of an ultraviolet spectrophotometric method for the determination of trace amounts of phenols with iodine monobromide
A procedure for the spectrophotometric determination of microgram amounts of phenols by reaction with iodine monobromide was improved and its application extended. The reactions of 28 individual phenols were investigated and the precision and sensitivity of the method were enhanced when iron(III) sulfate was used as a catalyst. The adverse effects of reducing compounds were removed by addition of potassium bromate and interferences from some organic acids were decreased by preliminary extraction into cyclohexane. Interferences from phenylamine compounds proved more intractable and could not be removed by preliminary extraction. Rinsing the organic phase with anhydrous sodium sulfate powder dispersed any emulsion formed. Standard mixtures of phenols are proposed as standards for the analysis of waste water and whisky for total phenol content.