Sub-second adsorption for the fast sub-nanomolar monitoring of Clindamycin in its pure and pharmaceutical samples by fast Fourier transformation with the use of continuous cyclic voltammetry at an Au microelectrode in a flowing system

For the first time the fast Fourier arlsorptive stripping voltammetry at a microgold electrode for the determination of Clindamycin in flow injection systems has been developed. The principal advantages of the method are that it is rapid, simple, and possesses low detection limit. Some investigations were also done, to find the effects of various parameters on the sensitivity of the proposed method. The conditions producing the performance were the PH value of 2, the scan rate value of 40 V/s, accumulation potential of (300 mV), and accumulation time of 0.3 s. Some of the advantages of the proposed method are as follows: the removal of oxygen from the test solution is not required any more, the detection limit of the method is sub-nanomolar and finally, the method is fast enough for determination of such compounds, in a wide variety of chromatographic methods. We also introduce a special computer based numerical method, for calculation of the analyte signal and noise reduction. After subtracting the background current from noise, the electrode response was calculated, based on partial and total charge exchanges at the electrode surface. The integration range of currents was set for all the potential scan ranges, including oxidation and reduction of the Au surface electrode, to obtain a sensitive determination. The waveform potential was continuously applied on an An disk microelectrode (with a 12.5 mu m in radius). The method was linear over the concentration range of 4-42,498,400 pg/ml (r= 0.9957) with a limit of detection and quantitation 1.3 and 4 pg/ml, respectively. The method has the requisite accuracy, sensitivity, precision and selectivity to assay Clindamycin in capsules. (C) 2007 Elsevier B.V. All rights reserved.