Talanta 82 (2010) 1864–1869 Contents lists available at ScienceDirect Talanta journal homepage: www.elsevier.com/locate/talanta Application of surfactant assisted dispersive liquid–liquid microextraction for sample preparation of chlorophenols in water samples Morteza Moradi, Yadollah Yamini ∗ , Ali Esrafili, Shahram Seidi Department of Chemistry, Faculty of Sciences, Tarbiat Modares University, P.O. Box 14115-175, Tehran, Iran article info Article history: Received 10 June 2010 Received in revised form 31 July 2010 Accepted 3 August 2010 Available online 10 August 2010 Keywords: Surfactant assisted dispersive liquid–liquid microextraction Chlorophenols Natural water samples High performance liquid chromatography abstract A simple, rapid, and efficient method, based on surfactant assisted dispersive liquid–liquid microextrac- tion (SA-DLLME), followed by high performance liquid chromatography (HPLC) has been developed for the extraction and determination of chlorophenols as model compounds in environmental water sam- ples. A conventional cationic surfactant called cethyltrimethyl ammonium bromide (CTAB) was used as a disperser agent in the proposed approach. Thirty-five microliter of 1-octanol as an extraction solvent was injected rapidly into 11 mL aqueous sample containing 0.09 mmol L -1 of CTAB, the mixture was then shaken for 3 min to disperse the organic phase. Having the extraction procedure been completed, the mixture was centrifuged and 20 L of collected phase was injected into HPLC for subsequent analysis. Some parameters such as the type and volume of the extraction solvent, the type and concentration of surfactant, pH, ionic strength, shaking time, extraction temperature and centrifugation time were optimized. The preconcentration factors (PFs) in a range of 187–353 were obtained under the optimum conditions. The linear range, detection limit (S/N = 3), and precision (n = 5) were 0.2–200, 0.1 gL -1 , and 4.7–6.9%, respectively. Tap water, sea water and mineral water samples were successfully analyzed for the existence of chlorophenols using the proposed method. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Phenol and substituted phenols are widely distributed in natural waters because of their wide use in many industrial processes such as the manufacture of plastics, dyes, drugs and pesticides [1–3]. Among these compounds, chlorophenols are well known pollutants because of their toxicity in aquatic life and poor biotreatability, and since they make an unpleasant taste and odor in water even in very low concentrations. Chlorophenols are formed by the degra- dation of phenoxy herbicides, as well as by the chlorination of drinking water containing aromatic impurities [4–6]. The European Community legislation has also set a maximum allowable phe- nol concentration of 0.5 gL -1 in tap water [7]. The importance of chlorophenols in environment, calls for sensitive and reliable methods to determinate them in water samples. Many methods for analysis of chlorophenols are based on chromatographic tech- niques such as high performance liquid chromatography (HPLC) [8–10], gas chromatography (GC) [11–13] and capillary elec- trophoresis [14,15]. The GC analysis of the chlorophenols leads to tailed peaks resulting decreasing the detection limits and the reli- ability of the results. To alleviate this drawback, chlorophenols are usually derivatized with a suitable derivatization reagent before ∗ Corresponding author. Tel.: +98 21 82883417; fax: +98 21 88006544. E-mail address: yyamini@modares.ac.ir (Y. Yamini). injection into the GC. On the other hand, HPLC is a good alterna- tive technique, in which isocratic or gradient elution can be used to separate the compounds. In general, the environmental samples are too diluted or too complex. Therefore, prior to analysis by HPLC, a sample prepa- ration step is necessary to extract traces of chlorophenols from the aqueous medium, bring the analytes to a suitable concentra- tion level, and remove them from interfering components in the matrix [16]. Typically, this would require an extraction step such as liquid–liquid extraction (LLE) or solid phase extraction (SPE). How- ever, conventional LLE consumes large amounts of the high costing and potentially hazardous organic solvents. In addition, in trace analysis, a large volume of sample is often required and its handling can be extremely time consuming besides being tedious. SPE uses much less solvent and is less time consuming than LLE but requires column conditioning and is relatively expensive [17]. The first attempts to miniaturize the conventional LLE have been developed by Liu and Dasgupta [18,19] and Jeannot and Cantwell [20]. The first suggested method of liquid phase microextraction (LPME) was a single drop microextraction (SDME). This technique is performed by suspending a microliter drop of organic solvent in the stirred aqueous solution, in which the analytes are partitioned between the organic drop and the aqueous phase. Several different types of LPME methods have been developed, including hollow fiber LPME [21], homogeneous liquid–liquid extraction (HLLE) [22,23] and solidification of a floating organic drop (SFO) [24]. Microextraction 0039-9140/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.talanta.2010.08.002