HIGHLY-SENSITIVE MEASUREMENT OF HYDROQUINONE WITH AN ENZYME ELECTRODE

An enzyme electrode with a chemically amplified response for hydroquinone and other dihydroxyphenols, such as catechol, dopamine, norepinephrine, and epinephrine, is constructed from a glassy carbon electrode and a layer containing immobilized glucose oxidase. Dihydroxyphenol molecules are consumed at the electrode surface but are regenerated by the glucose oxidase reaction in the layer. The consumption/regeneration cycle for dihydroxyphenols results in an electrode response amplified 2-120 times, and, accordingly, in an increased sensitivity. The detection limit of hydroquinone, catechol, or dopamine is as low as 1 nM.