Sequential solid phase extraction protocol followed by liquid chromatography–atmospheric pressure chemical ionization–mass spectrometry for the trace determination of non ionic polyethoxylated surfactants in tannery wastewaters

Automated solid-phase extraction (SPE) with C18 and styrene–divinylbenzene cartridges in series was used for the preconcentration of non ionic polyethoxylated surfactants in tannery wastewater. Fractionated extracts were analyzed by LC–MS using Atmospheric Pressure Chemical Ionization (APCl) in the Positive and Negative Ion modes. Recoveries for nonionic surfactants were approximately of 72, 90 and 80% for polyethylene glycols, nonylphenol and alcohol ethoxylates in the polar, aromatic and medium polarity fractions, respectively. Data acquisition in the selected ion monitoring mode afforded limits of quantification from 0.1 to 0.8 μg/l for tridecylic polyethoxylated alcohol and polyethoxylated glycol, respectively, in the complex tannery wastewaters. The tannery effluents investigated contained between 0.03 to 3.0 mg/l of polyethylene glycol and nonylphenol polyethoxylate, respectively.