In-sample acetylation-non-porous membrane-assisted liquid–liquid extraction for the determination of parabens and triclosan in water samples

Abstract

A procedure for the determination of seven parabens (esters of 4-hydroxybenzoic acid), including the distinction between branched and linear isomers of propyl- and butyl-parabens and triclosan in water samples, was developed and evaluated. The procedure includes in-sample acetylation-non-porous membrane-assisted liquid-liquid extraction and large volume injection-gas chromatography-ion trap-tandem mass spectrometry. Different derivatisation strategies were considered, i.e. post-extraction silylation with N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide and in situ acylation with acetic anhydride (Ac(2)O) and isobutylchloroformate. Moreover, acceptor solvent and the basic catalyser of the acylation reaction were investigated. Thus, in situ derivatisation with Ac(2)O and potassium hydrogenphosphate (as basic catalyser) was selected. Potassium hydrogenphosphate overcomes some drawbacks of other basic catalysers, e.g. toxicity and bubble formation, while leads to higher responses. Subsequently, other experimental variables affecting derivatisation-extraction yield such as pre-stirring time, salt addition and volume of Ac(2)O were optimised by an experimental design approach. Under optimised conditions, the proposed method achieved detection limits from 0.1 to 1.4 ng L(-1) for a sample volume of 18 mL and extraction efficiencies, estimated by comparison with liquid-liquid extraction, between 46% (for methyl- and ethyl-parabens) and 110% (for benzylparaben). The reported sample preparation approach is free of matrix effects for parabens but affected for triclosan with a reduction of approximately 40% when wastewater samples are analysed; therefore, both internal and external calibration can be used as quantification techniques for parabens, but internal standard calibration is mandatory for triclosan. The application of the method to real samples revealed the presence of these compounds in raw wastewater at concentrations up to 26 ng mL(-1), the prevalence of the linear isomer of propylparaben (n-PrP), and the coexistence of the two isomers of butylparaben (i-BuP and n-BuP) at similar levels.

Occurrence and risk assessment of parabens and triclosan in surface waters of southern Brazil: a problem of emerging compounds in an emerging country

“…Evaluation of compounds occurrence such as triclosan and parabens in water environments in the world are still limited to only a few studies on a reduced number of countries (Tables 2 and 3). Among the available studies, it as possible to observe a predominance of studies conducted in developed countries, especially those carried out in Spain (KANTIANI et al, 2008;REGUEIRO et al, 2009;MONTES et al, 2009;VILLAVERDE-DE-SÁA et al, 2010;GORGA;BARCELO, 2013). Complementarily, there was a trend of the highest concentrations of these compounds found in water samples in developing countries such as China (PENG et al, 2008), India (RAMASWAMY et al, 2011) and Brazil (this study).…”

“…Due to its high consumption, parabens have been found in various surface water matrices (BENIJTS; LAMBERT; LEENHEER, 2004;JONKERS et al, 2009;VILLAVERDE-DE-SÁA et al, 2010;GORGA;BARCELO, 2013), air and dust samples (CANOSA et al, 2006), soil (FERREIRA; MÖDER; LAESPADA, 2011) and on sewage sludge (LEE; PEART; SVOBODA, 2005;ALBERO et al, 2012a;GASPERI et al, 2014).…”

“…Triclosan has been found in aquatic environments in different parts of the world (BENIJTS; LAMBERT; LEENHEER, 2004;PAULL, 2005;KASPRZYK-HORDERN;DINSDALE;GUWY, 2009;VILLAVERDE-DE-SÁA et al, 2010), in wastewater, seawater, soil, and sediments (LOPEZ-AVILA; HITES, 1980;OKUMURA;NISHIKAWA, 1996;LINDSTROM et al, 2002;MCAVOY et al, 2002;SINGER et al, 2002;CHAU;CAI, 2008).…”

Determination of biocides in different environmental matrices by use of ultra-high-performance liquid chromatography–tandem mass spectrometry

“…For example, clotrimazole, ketoconazole, miconazole, fluconazole, and carbendazim have been detected in Belgian WWTP effluents at concentrations up to 27,90,36,140, and 980 ngL −1 , respectively [6], and climbazole and thiabendazole have been found in German WWTP effluents at average concentrations of 443 and 8.2 ngL −1 [7]. The insect repellent DEET has frequently been detected in WWTP effluents at concentrations ranging between 51 and 773.9 ngL −1 [8][9][10][11], and methylparaben, ethylparaben, propylparaben, and butylparaben in Spanish rivers and 4,5-dichloro-2-n-octylisothiazolinone (DCOIT) in Spanish coastal regions have been detected at maximum concentrations of 54, 30, 105, 7, and 3700 ng L −1 , respectively [12][13][14][15]. Triclosan has been found in 19 Australian WWTPs at average concentrations of 142 ngL −1 for effluents and 5.58 mgkg −1 for biosolids [16].…”

Gas chromatographic determination of parabens afterin-situderivatization and dispersive liquid-liquid microextraction

“…Because of the wide use, parabens are continuously released into the environment [3,4]. The presence of parabens was determined in wastewater [5][6][7][8][9][10], swimming pool water [8,9,11], river water [7][8][9][10]12], and even in tap water [6].…”