The electrochemical oxidation of penicillins on gold electrodes

Abstract

Penicillins can be electrochemically oxidized on gold electrodes in the presence of a catalytic surface oxide. Although oxidation can occur throughout a wide range of pH values, an acetate buffer solvent was selected to maximize the sensitivity and stability. Several amperometric waveforms were tested for penicillin detection using flow injection analysis. The use of pulsed amperometric detection (PAD) allowed the penicillins to be monitored either directly or indirectly depending on the specified waveform. Direct detection using standard PAD proved to be the optimal detection method, featuring excellent reproducibility and detectability to 4 X lo-' M for penicillin G.

Assay for Cephapirin and Ampicillin in Raw Milk by High-Performance Liquid Chromatography−Integrated Pulsed Amperometric Detection

“…A subsequent oxidation for cephapirin is not observed because the fully formed monolayer of gold oxide on the electrode surface blocks all other electrode reactions. 20,24,25 On the reverse scan, only the signal for the reduction of the monolayer of gold oxide is observed. Figure 1B shows the response for cephapirin in 4% acetonitrile, 500 mM sodium acetate buffer pH 3.75.…”

“…Unfortunately, formation of the gold oxide is associated with unstable baselines and large background signals. To alleviate these problems, a linear, cyclic scan between two potentials is performed during the detection step. − This detection scheme is called integrated pulsed amperometric detection (IPAD). The potential scanning allows the charge from oxide formation to be electronically subtracted from the total signal.…”

“…To alleviate these problems, a linear, cyclic scan between two potentials is performed during the detection step. [17][18][19][20] This detection scheme is called integrated pulsed amperometric detection (IPAD). The potential scanning allows the charge from oxide…”

Mineralisation of the antibiotic amoxicillin in pure and surface waters by artificial UVA‐ and sunlight‐induced Fenton oxidation

“…8,9 The advanced oxidation of amoxicillin in various matrices has only scarcely been reported in the scientific literature. Amoxicillin was found to be susceptible to electrochemical oxidation over gold 10 and modified carbon 11 electrodes, ozonation, 12 photoFenton oxidation 8,13 and oxidation with chlorine dioxide. 14 In other studies, 8,9 actual penicillin formulation effluents containing amoxicillin as the active substance were treated by several processes such as ozonation, perozonation, Fenton and photoFenton oxidation to evaluate the effect of chemical pre-oxidation on subsequent biodegradability.…”

Pulsed potentiometric detection in capillary electrophoresis using platinum electrodes

“…[21][22][23][24][25] The general term PED refers to any electrochemical detection scheme based on the application of multi-step waveforms (pulses of positive or negative potential) prior to and immediately after measurement intervals, regardless of the specific signal measured. 20 To date, the term has included several techniques measuring current, namely pulsed amperometric detection [26][27][28][29][30][31] pulsed coulometric detection 17,32 and pulsed voltammetric detection. 21,22,33 However, to our knowledge this principle has not been reported previously for potentiometric detection in flowing systems.…”