Nano-Level Detection of Naltrexone Hydrochloride in Its Pharmaceutical Preparation at Au Microelectrode in Flowing Solutions by Fast Fourier Transforms Continuous Cyclic Voltammetry as a Novel Detector

An easy and fast Fourier transform continuous cyclic voltammetric technique for monitoring of ultra trace amounts of naltrexone in a flow‐injection system has been introduced in this work. The potential waveform, consisting of the potential steps for cleaning, stripping and potential ramp, was continuously applied on an Au disk microelectrode (with a 12.5 µm in radius). The proposed detection method has some of advantages, the greatest of which are as follows: first, it is no more necessary to remove oxygen from the analyte solution and second, this is a very fast and appropriate technique for determination of the drug compound in a wide variety of chromatographic analysis methods. The method was linear over the concentration range of 0.34-34000 pg/mL (r = 0.9985) with a limit of detection 8.0 × 10−4 nm. The method has the requisite accuracy, sensitivity, precision, and selectivity to assay naltrexone in tablets. The influences of pH of eluent, accumulation potential, sweep rate, and accumulation time on the determination of the naltrexone were considered. © 2007 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 96:2009-2017, 2007