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摘要
Herein, Fe3O4 magnetic nanoparticles (MNPs) were synthesized and characterized. Afterward, a magnetic carbon paste electrode (MCPE) was modified with MNPs via casting and drying MNPs on top of the MCPE (MCPE/MNP). Electrochemical behavior of the MCPE/MNP was studied by cyclic voltammetry in the presence of [Fe(CN)6]3ˋ/4ˋ as a redox probe, and surface of MNPs was evaluated as . The behavior of MCPE/MNP towards dopamine (DA) and ascorbic acid (AA) has been investigated by electrochemical methods, and the obtained results showed that the MCPE/MNP has adsorption behavior towards only DA. Based on this behavior, the DA molecules were pre-concentrated on top of the MCPE/MNP and followed with stripping in DA free solution. Subsequent to experimental and instrumental optimization, a calibration curve from to ˋM DA with , DL = ˋM DA, and RSD = 4.6%, was obtained in the presence of ˋM AA. Performance of the MCPE/MNP was successfully tested in a pharmaceutical sample. 1. Introduction Dopamine (DA) is one of the most important neurotransmitters. It plays a significant role in the functioning of central nervous, renal, and hormonal systems as well as in drug addiction and Parkinson＊s disease [1, 2]. Therefore, understanding its electrochemical properties and quantifying its presence in human body fluids are the most important. Dopamine can be easily oxidized electrochemically at conventional electrodes, which have been used to detect the neurotransmitter [3每7]. Apart from the need to reach low detection limits, determination of the DA is complicated by the coexistence of many interfering compounds. Among them, ascorbic acid (AA) is of particular importance [8]. Ascorbic acid accompanies DA in biological samples: for instance, in the extracellular fluid of central nervous system, AA is present at the 100每500ˋ米M concentration level, whereas the concentration of DA is less than 100ˋnM [9]. But, in the biological samples, the basic concentrations of DA and AA vary from region to region and time to time in an extremely wide range, from to ˋM [10]. Therefore, improving the sensitivity and especially the selectivity of working electrodes toward the DA has been a goal of researchers in this area. To meet this challenge, a variety of modified electrodes have been proposed. These include self-assembled monolayer electrodes [5每7], polymer electrodes [11, 12], and nanomaterial film electrodes [13每15]. However, in all cases two general strategies were employed for detection of DA; (i) separation of DA and AA oxidation potentials, or (ii) selective pre-concentration of DA and
- 出版日期2013
