Amperometric detection of glucose and ethanol in beverages using flow celland immobilised on screen-printed carbon electrode PQQ-dependent glucose or alcohol dehydrogenases

Enzyme electrodes containing pyrroloquinoline quinone (PQQ)-dependent alcoh ol (ADH) or glucose dehydrogenase (GDH) as a biological component in combin ation with 4-ferrocenylphenol (F-P) as electron transfer mediator between P QQ and a carbon surface were constructed. The transducer was based on scree n-printed carbon electrode modified with Fl? and enzyme. The biosensors wer e installed in a flow cell for glucose and ethanol measurements. The calibr ation graphs were linear up to 10 mM glucose and 1 mM ethanol. To eliminate the electrode background current, 2,4,7-trinitro-9-fluorenone (TNF) was el ectrochemically polymerised on the carbon electrode surface. Due to this pr ocedure, interfering compounds do not influence the electrochemical respons e of the sensor. The flow-through biosensor system was applied to measure t he glucose and ethanol concentration in various beverages containing 0.3-20 0 mM glucose and about 2 M ethanol. The glucose biosensor data correlated w ith those obtained by refractometric measurements. (C) 2001 Elsevier Scienc e B.V. All rights reserved.