Electrochemical evaluation of non-electroactive drug erythromycin in trace amount at biological samples by continuous cyclic voltammetry

A fast continuous cyclic voltammetry was used as a detection method for the monitoring of erythromycin in a flow-injection system. A special computer-based numerical calculation method (using Fast Fourier Transformation) is introduced here for enhancing the analyte signal and noise reduction. During the measurements, the potential waveform (consists of potential steps for cleaning, stripping and potential ramp) was continuously applied on an Au disk microelectrode with a 25 μm radius. The objective of the performed experiments was the inspection of the effects of different parameters on the method sensitivity. After the experiments' completion, it was concluded that the method was linear for the concentration range of 7–733,000 pg/ml (r = 0.998) with a limit of detection and quantitation 2.4 and 7 pg/ml, respectively. The stripping time was less than 200 ms. Effects of rest potential, sweep rate, and delay time on the sensitivity and selectivity of the method were investigated.