Subsecond FFT‐adsorptive Voltammetric Technique as a Novel Method for Subnano Level Monitoring of Piroxicam in its Tablets and Bulk Form at Au Microelectrode in Flowing Solutions

Abstract In this work a novel method for the determination of piroxicam in flow‐injection systems has been developed. A system using fast Fourier transform continuous cyclic voltammetry (FFTCV), at a gold microelectrode in flowing solution, was used for determining piroxicam in its pharmaceutical formulations. The developed technique is very simple, precise, accurate, time saving, and economical, compared to all of the previously reported methods. The effects of various parameters on the sensitivity of the method were investigated. The best performance was obtained with a pH value of 2, scan rate value of 40 V/s, accumulation potential of (400) mV, and accumulation time of 0.4 s. The proposed method has some advantages over other reported methods, such as, no need for the removal of oxygen from the test solution, a picomolar detection limit, and finally that the method is fast enough for the determination of any such compound, in a wide variety of chromatographic methods. To obtain a sensitive determination, the integration range of currents was set for all the potential scan ranges, including oxidation and reduction of the Au surface electrode, while performing the measurements. The potential waveform, consisting of the potential steps for cleaning, accumulation, and potential ramp of analyte, was applied on an Au disk microelectrode (with a 12.5 µm in radius) in a continuous way. The method was linear over the concentration range of 1.5–364000 pg/ml (r=0.998) with a limit of detection and quantitation of 0.33 and 1.5 pg/ml, respectively. The method has the requisite accuracy, sensitivity, precision, and selectivity to assay piroxicam in tablets.