Amperometric Detection of Alcohols and Carbohydrates Coupled with Their Electrocatalytic Oxidation by 2, 2, 6, 6-Tetramethylpiperidinyl-1-oxy (TEMPO)

Application of the well-known electrocatalytic oxidation of alcohols by 2, 2, 6, 6-tetramethylpiperidinyl-1-oxy (TEMPO) as a novel tool for the amperometric detection of alcohols under basic conditions has been examined. Cyclic voltammograms of TEMPO in the absence and the presence of 1-pentanol, diethyleneglycol, and glucose demonstrated that these alcohols can electrochemically detected in terms of the anodic response of an aqueous 150 mM NaOH solution of TEMPO at a glassy carbon electrode. In flow injection analysis (FIA) utilizing an aqueous 150 mM NaOH solution of 100 μM TEMPO as a carrier solution with an applied potential of 0.4 V vs. saturated calomel electrode (SCE) and a flow rate of 0.5 ml/min, a good dependency of FIA responses upon the concentration was observed for 1-pentanol (20 μM-1 mM), diethyleneglycol (5 μM-1 mM), and glucose (5 μM-1 mM). Reproducible and stable responses have been obtained for these alcohols on repetitive injections of the sample solutions. The results on the FIAs of various alcohols have demonstrated that the amperometric detection of primary alchols and especially polyhydroxylated compounds such as 1, ω-diols and carbohydrates can be achieved with a high sensitivity by the present methodology.