Determination of steroids in the dissolved and in the suspended phases of wastewater and Danube River samples by gas chromatography, tandem mass spectrometry Nóra Andrási, Borbála Molnár, Bernadett Dobos, Anikó Vasanits-Zsigrai, Gyula Záray, Ibolya Molnár-Perl n Institute of Chemistry, Department of Analytical Chemistry, L. Eötvös University, H-1518, P.O. Box 32, Budapest 112, Hungary article info Article history: Received 5 March 2013 Received in revised form 13 May 2013 Accepted 14 May 2013 Available online 20 May 2013 Keywords: Steroids Dissolved Suspended solids GC–MS/MS Wastewater Danube River abstract In this paper, a new working approach is described for the analysis of steroids as environmental water pollutants. As novelty to the field, steroids were identified and quantified both in the dissolved and in the suspended phases, as their trimethylsilyl-(oxime)-ether derivatives, applying a recently developed tandem gas chromatographic mass spectrometric (GC–MS/MS) method, applying multiple reaction monitoring (MRM) acquisition, suitable for their quantitation in the low ng/L level, in wastewater and in Danube River samples. In addition to the analysis of filtrates obtained by the common solid phase extraction (SPE) enrichment, even the insoluble, isolated by filtration prior to the SPE, and usually discarded part of steroids were identified and quantified, simultaneously, for the first time. For this purpose a new, time, labor, cost efficient and quantitative, ultrasound assisted extraction process was developed. Reproducibility, reliability and practical utility of the ultrasound assisted extraction process were proved by the proportionality of the extracted suspended steroids obtained from different sample volumes: prepared from 0.5 L and 1.0 L influent wastewater, as well as from 3 L, 5 L and 10 L Danube River water samples. Steroids' concentrations, identified and quantified in suspended conditions, showed proportionality, characterized with the relative standard deviation percentages (RSD%) of analyses: varying in case of Danube River water in the range of 0.92–6.0%, with an average of 4.10% RSD, while in the case of influent wastewater in the range of 1.59– 5.8%, with an average of 4.03% RSD. Partition of steroids, between the dissolved and suspended phases of influent and effluent wastewaters and river water samples, meaning, the total amounts of steroids that the ecosystem is liable to, were defined in river water samples for the first time. Distribution of found steroids revealed that their considerable and/or overwhelming part (relating to their total amounts), are present in suspended phases: in average, 71% from wastewater and 64% from Danube River samples. & 2013 Elsevier B.V. All rights reserved. 1. Introduction The presence of steroids in environmental waters, their hazardous effect on aquatic ecosystems is widely known; summed up also in our recent papers [1, 2] related to their identification and quantification, as their trimethylsilyl (oxime) ethers, by GC–MS/MS. In the knowledge of steroids' limited solubility we extended our attention from 2010 on to the analysis of the insoluble (suspended) parts of water samples, isolated by filtration and usually, discarded, except to a very recent, excellent two dimensional gas chromatography-time-of-flight mass spectrometry based analysis of wastewater samples, only [3]. Our decision was also inspired by the European Water Framework Directive (EWFD) [4] addressed to the Member States of the European Union, i.e., “As sediments appropriate for monitoring contaminants may not always be available…” consequently, “…suspended particulate matter as an alternative to sediments …” should be monitored [5]. Steroids' analysis in the suspended phases of environmental water samples is of primary importance since even under suspended conditions they are biologically available, as proven by bioassays [6,7], by in vitro [8] and by in vivo tests [9]. Suspended steroids contribute to the total estrogenic activities of waters [6], consequently, they should be considered as an integral part of environmental samples. Based on the overview of recent, relevant papers it turned out that distribution studies of steroids, performed simultaneously, between the dissolved and suspended phases, considering influent and effluent wastewater and river water samples are not available. Extraction approaches proposed for the analysis of the sus- pended phases proved to be labor-intensive and time-consuming. Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/talanta Talanta 0039-9140/$ - see front matter & 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.talanta.2013.05.029 n Corresponding author. Tel.: +36 1 372 26 16, fax: +36 1 372 25 92. E-mail addresses: perlne@chem.elte.hu, molnar.perl@gmail.com (I. Molnár-Perl). Talanta 115 (2013) 367–373