Nonelectroactive recognition: Monitoring of perphenazine by its subsecond adsorption on an Au microelectrode by the fast Fourier transform continuous cyclic voltammetric technique (FFTCCV)
A novel method for determining perphenazine in flow-injection systems has been developed in this work. The method was successfully applied for fast determination of perphenazine in its pharmaceutical formulations. Being very simple, precise, accurate, time-saving, and economical, this method has many advantages compared to all of the previously reported methods. Some investigations were also performed to find the effects of various parameters on the sensitivity of the proposed method. The conditions responsible for the performance were a pH value of 2, a scan rate value of 30 V/s, an accumulation potential of 500 mV, and an accumulation time of 0.8 s. Some of the advantages of the proposed method are as follows: the removal of oxygen from the test solution is not required anymore, the detection limit of the method is subnanomolar, and finally, the method is fast enough to determine such compounds in a wide variety of chromatographic methods. We also introduce a special computer-based numerical method to calculate the analyte signal and noise reduction. After subtraction of 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 Au disk microelectrode (a radius of 12.5 mu m). The detention limit of the method for perphenazine was 15 pg/ml. For eight runs, the relative standard deviation of the method at 1.1 x 10(-8) M was 2.1%.