Recent developments in surfactant analysis by ion chromatography

Abstract

A simple and sensitive method for analysing surfactants by ion chromatography (IC) is described. The method uses ion-pair separation with gradient elution and suppressed conductivity detection. Two types of suppressor devices are used. The electrochemically regenerated ion suppressor (ERIS; patent pending) is ideal for continuous unattended operation. It uses an electrochemical process to self-regenerate the suppressor cells. No regenerant reagent or system is required and no chemical waste is generated. This suppressor is compatible with up to 30% organic solvents in the mobile phase. For mobile phases containing higher organic concentration, the solid-phase chemical suppressor (SPCS) was used. The SPCS uses disposable suppressor cartridges as the suppression device. No regeneration or maintenance is needed with this suppressor since the cartridges are disposable. The SPCS cartridges are compatible with up to 80% organic solvents. Separation of surfactants was based on ion-pair interaction on a reversed-phase column. Both anionic and cationic surfactants can be determined using this method. The detection limits for the surfactants are in the parts-per billion and low parts-per million ranges.