The Immobilization of Fructose Dehydrogenase on Nanoporous Gold Electrodes for the Detection of Fructose

Nanoporous gold electrodes were utilized as a support for the detection of d-fructose. The immobilization of fructose dehydrogenase was achieved by adsorption on thiol- and diazonium-bound carboxylic acid functional groups and subsequent crosslinking through cabodiimide-initiated amide bond formation. The biosensor showed a linear response in the range 0.05–0.3 mM of d-fructose with a sensitivity of 3.7±0.2 μA cm⁻² mM⁻¹ and a limit of detection of 1.2 μM. The response of the biosensor in a range of natural sweeteners and beverages compared very favorably to the results obtained by a commercially available kit. Accurate readings were obtainable after a very fast response time of less than 5 seconds. The biosensor showed high specificity towards d-fructose in the presence of interfering sugars.