Electrochemical detection of alcohols and carbohydrates at a glassy carbon electrode coated with a poly(phenylene oxide) film containing immobilized 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)

Abstract

Electrochemical polymerization of 4-(3-hydroxyphenylacetyamino)-2,2,6,6- tetramethylpiperidinyl-1-oxyl (1) as a tool to immobilize 2,2,6,6- tetramethylpiperidinyl-1-oxyl (TEMPO) to the surface of a glassy carbon (GC) electrode has been examined. Voltammetric studies showed that anodic treatment in H2O-MeCN (4:1) containing 1, NaHCO3, and NaClO4 with cycled or constant potentials provides access to a GC electrode coated with a poly(phenylene oxide) film containing immobilized TEMPO, which functions well as a catalyst for the electrochemical oxidation of alcohols. The TEMPO- modified electrode was applied to flow injection analysis (FIA) of alcohols and carbohydrates with an amperometric mode at a low applied potential. The results of FIAs demonstrated that reproducible and stable responses in the present system are obtained, not for hydrophobic alcohols, but for hydrophilic ones such as carbohydrates, although the former will be detected with a higher sensitivity than the latter. The observed phenomena seem to originate from the interaction of both alcohols and their oxidized products with the hydrophobic poly(phenylene oxide) film on the electrode surface.