Cobalt Flower-like Nanostructure as Modifier for Electrocatalytic Determination of Chloropheniramine Mandana Amiri,* ,† Mohsen Alimoradi, ‡ Khadijeh Nekoueian, ‡ and Abolfazl Bezaatpour † † Department of Chemistry, University of Mohaghegh Ardabili, Ardabil, Iran ‡ Department of Chemistry, Payame Noor University (PNU), Ardabil, Iran * S Supporting Information ABSTRACT: In this approach, flower-like cobalt with a hierarchical structure was applied as modifier for voltammetric determination of chlorpheniramine, which is an antihistaminic drug. The flower-like cobalt nanostructures were synthesized by using a simple chemical method. They have been characterized by using scanning electron microscopy and cyclic voltammetry. The carbon paste electrode modified with cobalt nanostructures shows an excellent electrocatalytic activity and sensitivity toward chlorpheniramine due to its unique properties such as high specific surface area and large pore volume. Potential sweep rate and pH effects on the response of the electrode for the oxidation of chlorpheniramine were investigated. Differential pulse voltammetry has been applied for quantitative determination of chlorpheniramine. A dynamic linear range was obtained in the range of 1.0 × 10 -7 -1.0 × 10 -5 mol L -1 , and the detection limit was estimated to be 8.0 × 10 -8 mol L -1 . ■ INTRODUCTION Chlorpheniramine or chlorphenamine is a first-generation alkylamine antihistamine which is used in the prevention of the symptoms of allergic conditions such as rhinitis and urticaria (Scheme 1). 1 Several methods have been reported for the determination of chlorpheniramine maleate including spectrophotometry, 2 liquid chromatography, 3 mass spectrome- try, 4 gas chromatography. 5 These methods are time-consuming, solvent-usage intensive, and require expensive devices and maintenance. Electrochemical methods have attracted much interest as sensors due to the high sensitivity and desirable selectivity in their responses. Compared to other mentioned analytical techniques, electrochemical methods are simple, inexpensive, and easy to use. There are just few reports for the determination of chlorpheniramine by using electrochemical methods. 6-9 Over the past five decades, carbon paste, that is, a mixture of carbon (graphite) powder and a binder (pasting liquid), has become one of the most popular electrode materials used for the laboratory preparation of various electrodes, sensors, and detectors. Such a position is undoubtedly the result of optimal constellation of physicochemical and electrochemical properties of this carbon-like substrate. 10 The carbon paste electrodes have great compatibility with chemical modification. They can be modified by using various electron transfer mediators such as nanomaterials, 11,12 metal complexes, 13,14 zeolites, 15 and organic compounds. 16,17 In recent years, metal nanostructures such as cobalt, nickel, and iron, and so forth have attracted attention in electroanalysis because of their unusual physical and chemical properties. Metal nanostructures-modified electrodes usually exhibit high electrocatalytic activities toward compounds with sluggish redox processes at bare electrodes. Cobalt nanostructures have been used as a modifier for the determination of thioridazine, 18 nitrite, 19 and arsenic(III) 20 recently. Several cobalt nanostructures with various morphologies such as nanoparticles, nanorods, nanocubes, nanowires, flowers, hollowspheres, nanoboxes, and porous structures have been synthesized by means of various routes. They have attracted special interest because of their potential applications as sensors, heterogeneous catalysts, electrochromical devices, and magnetic materials. 21-25 In this approach we attempt to synthesis flower-like cobalt with a hierarchical structure with high specific surface area and large pore volume for the application in sensors, simply. They have been applied as a modifier in a carbon paste electrode for voltammetric determination of chlorpheniramin using differ- ential pulse voltammetry (DPV). This modified electrode also was applied as a sensitive sensor for the determination of chlorpheniramin in synthetic serum and pharmaceutical preparations. ■ EXPERIMENTAL SECTION Instrumentation. Voltammetric experiments were per- formed with a Metrohm Computrace voltammetric analyzer model 797VA. A conventional three-electrode system was used with a carbon-paste working electrode (unmodified or modified), a saturated Ag/AgCl as reference electrode and a Received: June 25, 2012 Revised: September 5, 2012 Accepted: October 16, 2012 Published: October 29, 2012 Scheme 1. The Structure of Chlorpheniramine Article pubs.acs.org/IECR © 2012 American Chemical Society 14384 dx.doi.org/10.1021/ie3016736 | Ind. Eng. Chem. Res. 2012, 51, 14384-14389