Development of a simple, low cost chronoamperometric assay for fructose based on a commercial graphite-nanoparticle modified screen-printed carbon electrode

This paper describes the development of a simple, low cost chronoamperometric assay, for the measurement of fructose, using a graphite-nanoparticle modified screen-printed electrode (SPCE-G-COOH). Cyclic voltammetry showed that the response of the SPCE-G-COOH enhanced the sensitivity and precision, towards the enzymatically generated ferrocyanide species, over a plain SPCE; therefore the former was employed in subsequent studies. Calibration studies were carried out using chronoamperometry with a 40 mu l mixture containing fructose, mediator and FDH, deposited onto the SPCE-G-COOH. The response was linear from 0.1 mM to 1.0 mM. A commercial fruit juice sample was analysed using the developed assay and the fructose concentration was calculated to be 477 mM with a precision of 3.03% (n = 5). Following fortification (477 mM fructose) the mean recovery was found to be 97.12% with a coefficient of variation of 6.42% (n = 5); consequently, the method holds promise for the analysis of commercial fruit juices.