Flow-injection analysis of residual glucose in wines using a semiautomatic analyzer equipped with a Prussian blue-based biosensor

The Prussian Blue modified glassy-carbon (GC) electrode assembled with glucose oxidase (GOD) immobilized in Nafion on the top of the electrode surface area has been inserted in a wall-jet cell connected to a semiautomatic analyzer, which controls all the operations for carrier buffer, flow and sample injection. The Prussian Blue based glucose biosensor inserted in the FIA analyzer has shown linear response to glucose at an applied potential of 0.0 V (Ag/AgCl) in the range of 10(-6)-10(-3) M. Residual glucose has been detected in red and white wines. A dilution of 1:1000 has been used for all the wines tested. Neither matrix effect, nor electrochemical interferences were observed. A comparison with a spectrophotometric glucose kit gave excellent correlation for levels of glucose detected. FIA analyzer compared with the standard analytical kit resulted in simplified procedures and a reduced time for the analysis