Development of Simple Test for Ethoxylated Nonionic Surfactants

Abstract

A rapid and simple method for the determination of nonionic surfactants is described. The method is based on the formation of an ion associate with a tetrabromophenolphthalein ethyl ester potassium salt and a potassium complex of Triton X-100 as an example of a nonionic surfactant. The ion associate is adsorbed to the inner wall of the vessel with vigorous shaking. After the complete removal of the solution in the tube, the ion associate was dissolved in ethanol and quantified spectrophotometrically. The proposed method is simple and rapid. The linear calibration curve for Triton X-100 was obtained at 1-5mg l^-1. The coefficient of variation for Triton X-100 at 5μg·l^-1 was 8.75% (n=9). The influence of the anionic surfactant used in this method was blocked by treatment with an anionic exchange resin.