Surfactants: non-biodegradable, significant pollutants in sewage treatment plant effluents: Separation, identification and quantification by liquid chromatography, flow-injection analysis—mass spectrometry and tandem mass spectrometry

Abstract

Effluents from biological waste water treatment plants contain mainly non-biodegradable polar compounds. Methods for the detection, identification and determination of these hardly or non-eliminatable polar organic compounds are described. Flow-injection analysis (FIA) and liquid chromatographic (LC) separation on an analytical column by mass spectrometric (MS) and tandem mass spectrometric (MS-MS) detection coupled by a thermospray (TSP) interface were performed. The results showed that non-ionic surfactants and their metabolites (primary degradation products) besides linear alkyl benzene sulphonates (LABS) may dominate the range of pollutants. LC-MS confirmed that retention time shifts may occur if waste water extracts are separated on analytical columns. This cannot be recognized by UV detection. The identification of a biochemical degradation product of a non-ionic surfactant was carried out by both FIA-MS-MS and LC-MS-MS. Quantification of this compound was performed by standard addition analysis using FIA-MS or LC-MS in the selected-ion monitoring (SIM) mode. The time required for quantification is 25–30 times higher using LC-MS instead of FIA-MS.