Improved Long-Term Reproducibility for Pulsed Amperometric Detection of Carbohydrates via a New Quadruple-Potential Waveform

Abstract

A new quadruple-potential waveform is introduced for detection of carbohydrates using pulsed amperometry. The new waveform cleans the electrode by application of a potential more negative than the potential limit. In contrast to a commonly used triple-potential waveform, negative cleaning allows the time during which gold oxide is formed to be minimized, thus minimizing the dissolution and resulting recession of the gold working electrode as a result of gold oxide formation/reduction cycles. Preventing gold electrode recession is shown to improve long-term reproducibility. Waveform parameters were chosen to maximize signal-to-noise ratio and freedom from electrode fouling caused by matrix components in the sample. Compared to the triple-potential waveform, the quadruple-potential waveform shows similar minimum detection limits but greatly improved long-term reproducibility.

Determination of IPTG in Recombinant Human Growth Hormone with Ion Chromatography and Pulsed Electrochemical Detection

“…On-line degassing as part of the solvent delivery system can relax constraints on the start/end potential [25]. The detection steps in both waveforms are followed by a large negative potential pulse (-2000 mV for 10 ms) to induce both cathodic cleaning of the electrode [26] and reduce any partly-soluble Au [27]. This potential pulse is necessary to extend the life of the electrode for months of continuous use.…”

Optimizing the Quadruple‐potential Waveform for the Determination of Gentamicin Sulfate by High Performance Liquid Chromatography with Pulsed Electrochemical Detection

“…In the quadruple-potential waveform, a high positive cleaning potential is replaced with a high negative one. According to Rocklin et al, 22 the possible mechanism of cleaning at negative potential is that the reaction products and other impurities adsorbed on the surface of electrode can be displaced by hydrogen atoms produced from the reduction of water. The effect of cleaning potential E2 on the peak areas of five gentamicin components was examined in the potential range of -1.2--2.0 V and the results are shown in Figure 4.…”

“…However, the hydroxyl and amino groups of its molecule structure present the possibility of detecting gentamicin by electrochemical method as used for the determination of amino acids and carbohydrate. [22][23][24][25][26][27][28][29][30][31][32][33] Several papers have been published for the determination of gentamicin by HPLC with pulsed amperometric detection (PAD). 4,34 In these methods, gentamicin can be separated by HPLC and then oxidized and detected at gold electrodes in a high pH solution.…”

“…A major drawback of the triple-potential waveform is a slow dissolution and recession of the surface of gold working electrode from an excessive oxidation of gold on the electrode surface during the cleaning step, which makes thin-layer channel thickness increase, and therefore causes a decrease in detection sensitivity and reproducibility. To overcome this disadvantage, Jensen et al 35 and Rocklin et al 22 advanced a novel quadruple-potential waveform and applied it successfully to detection of carbohydrates. Clarke et al 23 further developed this quadruple-potential waveform to six-potential waveform for the detection of amino acids and amino sugars.…”

Characterization and photocatalytic activity of transition-metal-supported surface bond-conjugated TiO2/SiO2

“…The parameters in these old waveforms are not suitable to apply in ED50 (Dionex) with smaller amperometric cell (Au electrode 1 mm i.d., cell volume 0.2 l) that is now commonly used. Jensen and Johnson [12] and Rocklin et al [13] successfully introduced high frequency waveforms for detection of carbohydrates by using smaller amperometric cell, respectively. Compared to the triple-potential waveform, the quadruplepotential waveform showed long-term reproducibility.…”