Talanta 84 (2011) 905–912 Contents lists available at ScienceDirect Talanta journal homepage: www.elsevier.com/locate/talanta A novel high selective and sensitive metronidazole voltammetric sensor based on a molecularly imprinted polymer-carbon paste electrode Mohammad Bagher Gholivand ∗ , Maryam Torkashvand Department of Analytical Chemistry, Faculty of Chemistry, Razi University, Kermanshah, Iran article info Article history: Received 6 December 2010 Received in revised form 10 February 2011 Accepted 16 February 2011 Available online 22 February 2011 Keywords: Metronidazole Molecularly imprinted polymer Cathodic stripping voltammetry Carbon paste abstract The design and construction of a highly selective voltammetric sensor for metronidazole by using a molec- ularly imprinted polymer (MIP) as recognition element were introduced. A metronidazole selective MIP and a nonimprinted polymer (NIP) were synthesized and then incorporated in the carbon paste electrodes (CPEs). The sensor was applied for metronidazole determination using cathodic stripping voltammetric method. The MIP–CP electrode showed very high recognition ability in comparison to NIP-CPE. Some parameters affecting the sensor response were optimized and then the calibration curve was plotted. Two dynamic linear ranges of 5.64 × 10 −5 to 2.63 × 10 −3 mg L −1 and 2.63 × 10 −3 to 7.69 × 10 −2 mg L −1 were obtained. The detection limit of the sensor was calculated as 3.59 × 10 −5 mg L −1 . This sensor was used successfully for metronidazole determination in biological fluids. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Metronidazole is a nitroimidazole derivative and has been widely used for the treatment of protozoal diseases including trichomoniasis and giardiasis [1]. This drug is effective against trichomonas, Vincent’s organisms, and anaerobic bacteria. Veteri- narians also use metronidazole to treat bacterial infections as well as giardia in dogs and cats [2]. Metronidazole [3] contains a nitro group which is the electrochemically active reducible center. In the absence of oxygen the reduction process for nitroimidazoles is similar to that for nitrobenzene [4]. Several methods have been reported for determination of metronidazole which include potentiometric [5,6], polaro- graphic [7,8], gas chromatography [9,10], supercritical fluid chromatography [11], thin layer chromatography (TLC) [12], high- performance liquid chromatography (HPLC) [13–16], voltammetric [17], derivative spectrophotometry [18–20], luminescence [21], and spectrophotometry [22–24]. However, these methods have some drawbacks such as time consuming, narrow range of determi- nation, requirement of heating or extraction, the use of nonaqueous systems, stability of the colored product formed, etc. [25]. Hence, it is of primary importance to develop an alternative method for metronidazole determination with a high degree of selectivity and sensitivity. Chemically modified carbon paste electrodes (CMCPE) have been continued to be of a major concern during the past decade. ∗ Corresponding author. Tel.: +98 831 4274557; fax: +98 831 4274559. E-mail address: mbgholivand@yahoo.com (M.B. Gholivand). Furthermore a relatively large number of electrochemical research has been devoted to the development and applications of different types of CMCPE [26–31]. Modification of carbon paste electrodes with suitable materials facilitates the electrochemical reactions of the redox compounds to proceed without hindrance [32,33]. This phenomenon generally results increasing in selectivity and sensi- tivity of the determinations [34–36]. Molecularly imprinted polymers (MIPs) are extensively cross- linked polymers containing specific recognition sites with a predetermined selectivity for analytes. The procedure for syn- thesizing an MIP is based on the polymerization of a functional monomer and a cross-linking agent in the presence of a template. When the imprinted molecule is removed, the imprinted polymer with a high affinity for the template molecule is obtained. This affin- ity is due to the shape and the arrangement of the functional of the monomer units [37]. The MIPs are used as antibody like materials for high selectivity and sensitivity, chemical inertness, long-term stability, availability in large quantities, and insolubility in water and most organic solvents [38,39]. MIPs are promising materials continually being used in sensor fields such as recognition elements or modifying agents (instead of other commonly used modifiers). The application of MIPs in electrochemistry is rather recent and was directed to combine their intrinsic properties to selected elec- trochemical reactions, in order to improve the response of the electrode [40,41]. This study was led to the development of a new MIP modified electrode for the determination of metronidazole with improved qualities such as: simplicity of electrode preparation, a wider linear range, lower detection limit (DL), higher selectivity and more stabil- ity of the used modifier. The procedure was based on the reduction 0039-9140/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.talanta.2011.02.022