Analytica Chimica Acta 594 (2007) 240–247 Extracting syringe for extraction of phthalate esters in aqueous environmental samples Staffan Bergstr¨ om, Thaer Barri ∗ , Jan Norberg, Jan ˚ Ake J¨ onsson, Lennart Mathiasson Department of Analytical Chemistry, Lund University, P.O. Box 124, S-221 00 Lund, Sweden Received 10 March 2007; received in revised form 11 May 2007; accepted 11 May 2007 Available online 21 May 2007 Abstract The use of the extracting syringe (ESy), a fully automated membrane-based extraction technique, for analysis of phthalate esters in complex aqueous samples has been investigated. The ESy, working as an autosampler that combines the extraction process and injection into the gas chromatograph (GC) in one single step, is placed on top of the GC equipped with a flame ionisation detector. The aqueous samples are loaded in a tray and automatically extracted by employing microporous membrane liquid–liquid extraction principle. After the extraction, the extract is directly injected into the GC’s programmable temperature vaporisation injector. Six different phthalate esters were used as model compounds. Four extraction solvents were tested and the addition of sample organic modifier was examined. Toluene was the optimal solvent to use for extraction. Due to the large variation in polarity of phthalate esters, 50% methanol as organic modifier had to be added to the samples so as to extract the most nonpolar phthalate esters; di-2-ethylhexylphthalate and di-n-octylphthalate, whereas the other four relatively polar phthalate esters were extracted from unmodified samples. No significant difference between extraction of river water, leachate water from a landfill and reagent water was noted, except for minor deviations. The extraction time was 20min for extraction of a 1-mL sample, resulting in a good linearity for all aqueous media investigated, good enrichment factors (54–110 folds) and low LOD values (0.2–10 ng mL -1 ) and relative standard deviation (%R.S.D.; 0.9–3.7%). © 2007 Elsevier B.V. All rights reserved. Keywords: Extracting syringe; Membrane extraction; Microporous membrane liquid–liquid extraction; Phthalate esters; Environmental analysis; Leachate water; Gas chromatography 1. Introduction The international awareness of the impact of endocrine dis- rupting compounds on wellbeing of man and their far-reaching polluting effects on the environment has been markedly observed in the last few years. The phthalic acid diesters (phthalate esters) are classified among these compounds as they have been reported for their endocrine disrupting activity in humans and animals [1,2]. The physicochemical properties of phthalate esters make their use as plasticizers in the manufacturing of PVC resins, cellulose, clothes, adhesives, medical products and food packaging of indispensable value for the industry [3]. Because of the tremendous production and use of products containing phthalate esters, the products are directly or indirectly disposed ∗ Corresponding author. Tel.: +46 46 222 0369; fax: +46 46 222 45 44. E-mail address: thaer.barri@analykem.lu.se (T. Barri). into the environment. As phthalate esters are physically blended into the products, they are easily leached into the environment (i.e. biota and ecosystem) and food products, causing pollution. Phthalate esters are known as widespread contaminants [1–3]. The environmental pollution of phthalates has been found in sur- face water, ground water, drinking water, wastewater, sediments and air samples at ng mL -1 levels [4–9]. Accordingly, for phthalate esters analysis at trace levels in complex matrixes, such as water samples, developing fast and reliable analytical protocols is basically of significant importance for monitoring phthalate ester-contaminated sam- ples. In this context, the most frequently adapted extraction techniques available today are liquid–liquid extraction (LLE) and solid-phase extraction (SPE). The drawbacks of using these techniques are pretty much known, and thus have urged the scientists to quest for new innovative sample preparation pro- cedures. Subsequently, the attempts for miniaturisation of LLE [10–15] and modifications of SPE [5,6,16,17] have never been 0003-2670/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.aca.2007.05.015