Journal of Chromatography A, 1218 (2011) 3945–3951 Contents lists available at ScienceDirect Journal of Chromatography A journal homepage: www.elsevier.com/locate/chroma A new strategy to simultaneous microextraction of acidic and basic compounds Morteza Moradi, Yadollah Yamini ∗ , Jamal Kakehmam, Ali Esrafili, Mahnaz Ghambarian Department of Chemistry, Faculty of Sciences, Tarbiat Modares University, P.O. Box 14115-175, Tehran, Iran article info Article history: Received 13 February 2011 Received in revised form 21 April 2011 Accepted 21 April 2011 Available online 6 May 2011 Keywords: Ion pair based surfactant assisted microextraction Chlorinated aniline Nitrophenols High performance liquid chromatography Water sample abstract The simultaneous extraction of acidic and basic pollutants from water samples is an interesting and debatable work in sample preparation techniques. A novel and efficient method named ion pair based surfactant assisted microextraction (IP-SAME) was applied for extraction and preconcentration of five selected acidic and basic aromatic species as model compounds in water samples, followed by high per- formance liquid chromatography–ultraviolet detection. A mixture including 1 mL of ultra-pure water (containing ionic surfactant as emulsifier agent) and 60 L 1-octanol (as extraction solvent) was rapidly injected using a syringe into a 10.0 mL water sample which formed an emulsified solution. IP-SAME mech- anism can be interpreted by two types of molecular mass transfer into the organic solvent (partitioning and ion pairing for non-ionized and ionized compounds, respectively) during emulsification process. The effective parameters on the extraction efficiency such as the extraction solvent type and its volume, type of the surfactant and its concentration, sample pH and ionic strength of the sample were optimized. Under the optimum conditions (60 L of 1-octanol; 1.5 mmol L -1 cethyltrimethyl ammonium bromide (CTAB) as emulsifier agent and sample pH 10.0), the preconcentration factors (PFs), detection limits and linear dynamic ranges (LDRs) were obtained in the range of 87–348, 0.07–0.6 gL -1 and 0.1–200 gL -1 respectively. All of natural water samples were successfully analyzed by the proposed method. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Aromatic compounds such as aniline, phenol and their deriva- tives are of great importance in environmental chemistry due to their toxic nature and their suspected carcinogenic properties [1–3]. They are used in several manufacturing processes, partic- ularly in dye industry [4]. Also with the recent development of aniline and phenol-based herbicides, there has been a great deal of attention on aniline, phenol and their derivatives as environmen- tal pollutants. Due to their high solubility in water, anilines and phenols can easily permeate through soil and contaminate ground water. Aniline is highly toxic and readily absorbed through the skin in dangerous amounts and is fatal if swallowed or if the vapors are inhaled [5]. Chlorinated anilines (CAs) such as 3-chloroaniline, 4- chloroaniline and 3,4-dichloroaniline have also been found as degradation products and intermediates of various phenylurea and phenylcarbamate pesticides [6]. Regarding the importance of these compounds, a rapid and sensitive method of analysis is needed to detect them in the environment. ∗ Corresponding author. Tel.: +98 21 82883417; fax: +98 21 88006544. E-mail address: yyamini@modares.ac.ir (Y. Yamini). Nitrophenols (NPs) might be released due to the photochemical reaction of benzene with nitrogen monoxide in highly polluted air. Therefore, nitrophenols are found as contaminants in wastewater, rivers, groundwater, soil, and in the atmosphere. Concentrations in the range of 4.6–100 gL -1 have been found in rain water and in the tropospheric atmosphere [7]. Several analytical methods have been reported for determi- nation of anilines, phenols and their derivatives such as gas chromatography (GC) [8,9] and capillary zone electrophoresis (CZE) [10]. The most popular technique for the analysis of aromatic amines and phenols in environmental water is high-performance liquid chromatography (HPLC) [11]. Although the development of modern analytical instruments allows great enhancement in aspects of analysis, the available ana- lytical instrumentation does not have enough sensitivity for the analysis of natural samples in many cases. Sample preparation is still a bottleneck for overall throughput because the steps involved often employ large volumes of hazardous organic solvents, are time consuming and/or expensive. Besides, there might also be the prob- lem of contamination and sample loss [12–16]. Recently, liquid phase microextraction (LPME) was developed as a novel and disposable method for sample preparation [17]. LPME is a solvent-minimized sample preparation procedure, in which only several L of solvent are required to concentrate analytes from 0021-9673/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.chroma.2011.04.060