Determination of alcohol sulfates in wastewater treatment plant influents and effluents by gas chromatography-mass spectrometry C. Ferna ´ ndez-Ramos, O. Ballesteros n , R. Blanc, A. Zafra-Go ´ mez, I. Jime ´ nez-Dı ´az, A. Navalo ´ n, J.L. Vı ´lchez Research Group of Analytical Chemistry and Life Sciences, Department of Analytical Chemistry, University of Granada, Campus of Fuentenueva, E-18071 Granada, Spain article info Article history: Received 29 March 2012 Received in revised form 19 June 2012 Accepted 25 June 2012 Available online 29 June 2012 Keywords: Solid-phase extraction Hydrolysis Derivatization GC–MS Wastewater Alcohol sulfates Anionic surfactant abstract In the present paper, we developed an accurate method for the analysis of alcohol sulfates (AS) in wastewater samples from wastewater treatment plant (WWTP) influents and effluents. Although many methodologies have been published in the literature concerning the study of anionic surfactants in environmental samples, at present, the number of analytical methodologies that focus in the determination of AS by gas chromatography in the different environmental compartments is limited. The reason for this is that gas chromatography–mass spectrometry (GC–MS) technique requires a previous hydrolysis reaction followed by derivatization reactions. In the present work, we proposed a new procedure in which the hydrolysis and derivatization reactions take place in one single step and AS are directly converted to trimethylsilyl derivatives. The main factors affecting solid-phase extraction (SPE), hydrolysis/derivatization and GC–MS procedures were accurately optimised. Quantification of the target compounds was performed by using GC–MS in selected ion monitoring (SIM) mode. The limits of detection (LOD) obtained ranged from 0.2 to 0.3 mgL 1 , and limits of quantification (LOQ) from 0.5 to 1.0 mgL 1 , while inter- and intra-day variability was under 5%. A recovery assay was also carried out. Recovery rates for homologues in spiked samples ranged from 96 to 103%. The proposed method was successfully applied for the determination of anionic surfactants in wastewater samples from one WWTP located in Granada (Spain). Concentration levels for the homologues up to 39.4 mgL 1 in influent and up to 8.1 mgL 1 in effluent wastewater samples. & 2012 Elsevier B.V. All rights reserved. 1. Introduction In recent years, the contamination of environment by organic compounds (e.g., pharmaceuticals, surfactants, endocrine disrup- tors, polymers) has prompted the development of regulatory policies that reflects an increase in public concern about their potential, but still unknown, adverse effects on wildlife [1]. Water is the mainstay of any environment and water degradation may have serious environmental consequences. Protecting the water thus means protecting the surrounding ecosystems of which water is an integral part. Water is at great risk of contamination, which compromises the long-term availability of water, so mea- sures need to be taken in this respect to limit futher degradation of water and reverse negative trends towards quality improve- ment, protecting water and restoring the quality of water that is in poor condition. The implementation of European Directives 91/ 271/ECC [2] and 98/15/EEC [3] concerning urban wastewater treatment has increased the number of WWTPs operating in the European Union. Raw municipal wastewater usually undergoes mechanical treatment (primary sewage effluents, effluents from the pre-settling tank), and biological treatment (second sewage effluents, effluents from the settling tank after activated sludge treatment). Membrane bioreactor (MBR) is a promising technol- ogy for wastewater treatment, but there is not much information as to how organic pollutants behave in wastewater when these treatments are applied [4–6]. Surfactants are produced and consumed in large quantities, a result of their multiple applications (household and industrial cleaning products, personal care products, detergent formula- tions, emulsifiers, pesticides, adjuvants and wetting agents). More than 15 millions mt of surfactants are produced annually worl- wide [7]. Approximately 65% of this production corresponds to anionic surfactants, being alcohol sulfates (AS) one of the main groups of anionic sufactants, with an estimated annual produc- tion of 102,000 mt in Europe [8]. The main use of AS is household cleaning products and personal care products. The use of surfac- tants is therefore strongly associated with human and industrial activity and relatively large amounts of these compounds are being continously released into the environment. Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/talanta Talanta 0039-9140/$ - see front matter & 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.talanta.2012.06.065 n Corresponding author. Tel.: þ34 958 244077; fax: þ34 958 243328. E-mail address: oballest@ugr.es (O. Ballesteros). Talanta 98 (2012) 166–171