Prediction of the behaviour of organic pollutants using cloudpoint extraction

Abstract

A preconcentration study based on the cloud point phenomenon was carried out for a set of triazine herbicides, three of them chloro-substituted and three of them methylthio-substituted. Concentration factors and recoveries were calculated as function of the percentage of the non-ionic surfactant Triton X-114 employed. From these values, obtained from a cloud point extraction (CPE) procedure, the distribution coefficient between the Triton X-114 micelles and water, K c, prior to CPE was calculated for each triazine and related to the corresponding octanol–water partition coefficient, K ow, In order to confirm the results obtained with the triazine herbicides, two sets of data from chemically different organic pollutants—organophosporous and chlorophenols—obtained from the literature were assessed, concluding that they display a similar behaviour to that of the triazine herbicides. This can be used to predict the CPE behaviour of other organic pollutants from their octanol–water partition coefficients. The K c values were compared with the analyte concentration ratio in the surfactant-rich phase and aqueous phase ( K sa) with a view to obtaining a link between the analyte behaviour prior to and after cloud point extraction procedures.