The effect of pulsed amperometric detection on penicillin G concentration profiles in a flowing-stream environment

It is well known that alterations of the times and potentials of each step within a PAD waveform can alter the sensitivity of the amperometric response, peak shape has also been found to vary with waveform adjustments. This work studied the variation in both peak heights and peak tailing as a function of waveform alterations for penicillin G oxidation in flow injection analysis. Large variations were found when the detection step and adsorption time were altered and smaller changes were observed during alterations of the other parameters. The major contribution to the tailing profile was inefficient removal of adsorbed analyte, which was subsequently retained until further PAD cycles. Alterations that improved the desorption efficiency led to reduced peak tailing, whereas alterations that hindered desorption caused an increase in tailing. The ability to minimize peak tailing will be advantageous for PAD usage with separation methods featuring ever-increasing resolution capability.