Sensitized luminescence induced by nickel electrocatalysis to detect aliphatic hydroxy compounds

A well-defined luminescence, induced by the electrocatalytic oxidation of simple hydroxy compounds at a Ni electrode in alkaline media containing a fluorescent compound, has been studied with a view to make use of it for the sensitive detection of those compounds. For luminescent reactions with various substrates, including ethanol, polyols and glucose, the potentials required to elicit light were in the range of +0.4 to +0.5 V (vs. Ag/AgCl) where an active nickel(III) surface was anodically formed. This property was preserved in a flow-through system under the condition of constant-potential electrolysis at about +0.4 V (vs. AgCl coated on Ag). For ethanol, this luminescence in combination with liquid chromatographic separation allowed its determination in the range of 5×10−5 to 1×10−2 mol dm−3 with the lower limit of detection of ca. 0.5 nmol per 10 μl injection (signal-to-noise ratio=3).