Triple pulse amperometry: a method of detection of carbohydrates and alcohols for liquid chromatography
Is Version Of
Application of a triple pulse waveform is described for the anodic detection of simple alcohols and carbohydrates at a platinum electrode. The execution of the waveform incorporates the cleaning and reactivation of the platinum electrode, by alternate anodic and cathodic polarization, with measurement of the faradaic signal for the analyte at the reduced electrode surface. The waveform is completed within 0.5-1.5 s and the sampled faradaic signal exhibits no decay with time as would be the case for amperometric detection at a constant applied potential. Calibration curves made by plotting -1/I vs. 1/C are linear. This observation is consistent with a reaction mechanism in which the analyte is adsorbed prior to anodic detection;The technique was applied at a miniature platinum wire-tip electrode in a flow-through electrochemical detector for the determination of alcohols and carbohydrates separated by HPLC. A detection limit of 0.46 (mu)g (signal-to-noise = 2) was determined for glucose. The analysis of several real samples, including wine, beer and urine, is described for carbohydrates and alcohol.