Flow-injection photometric determination of the phenol index of natural waters in the presence of humic acids

Different schemes were considered for extraction preconcentration in the flow-injection determination of a phenol index, the total concentration of phenol and its derivatives that react with 4-aminoantipyrine. Preference was given to the scheme of flow injection analysis with the direct introduction of an extractant into the mixed flow of a sample and a reagent solution followed by phase separation in a chromatomembrane cell. This allowed phenols to be determined in natural and purified waste waters in the concentration range 1.0 to 10.0 µg/L with an RSD 25% and a throughput of 15 samples an hour. The study of the effect of humic acids on the results of determining the phenol index of natural waters showed that humic acids were hydrolyzed to form compounds that made their own contributions to the phenol index which were difficult to take into account.Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 1, 2005, pp. 79–84.Original Russian Text Copyright © 2005 by A. Moskvin, Mozzhukhin, Mukhina, L. Moskvin.