The analysis of surfactants and their determination in surface water by liquid chromatography and liquid chromatography-mass spectrometry.

Linear alkylbenzene sulphonates (LAS) and alkylphenol polyethoxylates (APEO), the surfactants most used in this country, are complex mixtures of oligomers and homologues. Due to their excellent surface active properties they are widely used as ingredients in many detergent formulations both in the home and more importantly in industry. For several years research has been carried out in order to understand the environmental impact of these widely used groups of compounds. However, some of the analytical techniques developed are not able to give reliable information concerning individual oligomer / homologue levels. As the toxicological profile of these compounds is dependent on the individual levels present this data is of great importance.Surfactants are most often introduced into the environment through wastewaters. In order to try and actively contribute to this area, laboratory investigations were undertaken to develop chromatographic techniques which would be able to determine individual oligomer / homologue levels in environmental surface water samples. Even if extensive sample clean up is used these samples are by nature, very 'complex'. Mass spectrometry lends itself to the analysis of environmental samples as it is able to give detailed structural data which aids in eliminating signal contributions from interfering compounds. To this end, work was carried out in order to develop liquid chromatography methods which are compatible with conventional mass spectrometers and could be used for the determination of the environmental levels of both LAS and APEO.