1 3 DOI 10.1007/s10337-013-2604-6 Chromatographia (2014) 77:329–336 ORIGINAL Homogeneous Liquid–Liquid Microextraction for Determination of Organochlorine Pesticides in Water and Fruit Samples Najmeh Yazdanfar · Yadollah Yamini · Mahnaz Ghambarian Received: 13 July 2013 / Revised: 8 October 2013 / Accepted: 11 November 2013 / Published online: 29 November 2013 © Springer-Verlag Berlin Heidelberg 2013 Keywords Gas chromatography · Electron capture detector · Homogeneous liquid–liquid microextraction · Organochlorine pesticides · Ternary component system Introduction Most organochlorine pesticides (OCPs) are persistent organic pollutants (POPs) in the environment. Nine of the OCPs were the subjects of the Stockholm convention on POPs. The proposed treaty called for urgent global actions to reduce and eliminate the release of these compounds [1]. They are a possible risk to the environment because of their toxicity and ability to bioaccumulate. Studies involv- ing determination of OCPs in environmental matrices often deal with samples with low analyte concentrations contain- ing a high number of interfering compounds. Thus, simple and highly efficient extraction and preconcentration meth- ods are required to detect trace levels of pollutants in water samples. OCPs can be extracted from aqueous matrices using a variety of conventional techniques including liquid–liquid extraction (LLE) [2] and solid-phase extraction (SPE) [3]. These techniques, whilst offering excellent recovery and analytical precision of OCPs, are also time consuming, expensive, and especially in relation to LLE, hazardous to health due to the high volume of toxic solvents used [4]. Although SPE consumes much less time than LLE, a sol- vent evaporation step before final analysis is required [5]. Solid-phase microextraction (SPME), a fast and solvent- free technique, overcomes the above problems [6]. How- ever, it has also some drawbacks such as high cost, sam- ple carry-over, and a decline in performance with time [7]. Recently, a solvent-minimized sample pretreatment proce- dure, known as liquid-phase microextraction (LPME), has Abstract A fast and effective preconcentration method for extraction of organochlorine pesticides (OCPs) was developed using a homogeneous liquid–liquid extraction based on phase separation phenomenon in a ternary solvent (water/methanol/chloroform) system. The phase separation phenomenon occurred by salt addition. After centrifuga- tion, the extraction solvent was sedimented in the bottom of the conical test tube. The OCPs were transferred into the sedimented phase during the phase separation step. The extracted OCPs were determined using gas chromatogra- phy–electron capture detector. Several factors influencing the extraction efficiency were investigated and optimized. Optimal results were obtained at the following conditions: volume of the consolute solvent (methanol), 1.0 mL; vol- ume of the extraction solvent (chloroform), 55 μL; vol- ume of the sample, 5 mL; and concentration of NaCl, 5 % (w/v). Under optimal conditions, the preconcentration fac- tors in the range of 486–1,090, the dynamic linear range of 0.01–100 μg L −1 , and the limits of detection of 0.001– 0.03 μg L −1 were obtained for the OCPs. Using internal standard, the relative standard deviations for 1 μg L −1 of the OCPs in the water samples were obtained in the range of 4.9–8.6 % (n = 5). Finally, the proposed method was successfully applied for extraction and determination of the OCPs in water and fruit samples. N. Yazdanfar · M. Ghambarian Iranian Research and Development Center for Chemical Industries (ACECR), P.O. Box 14155-175, Tehran, Iran Y. Yamini (*) Department of Chemistry, Faculty of Sciences, Tarbiat Modares University, P.O. Box 14115-175, Tehran, Iran e-mail: yyamini@modares.ac.ir