REAGENTLESS CHEMICALLY-MODIFIED CARBON-PASTE ELECTRODE BASED ON A PHENOTHIAZINE POLYMER DERIVATIVE AND YEAST ALCOHOL-DEHYDROGENASE FOR THE ANALYSIS OF ETHANOL
E. Dominguez et al., REAGENTLESS CHEMICALLY-MODIFIED CARBON-PASTE ELECTRODE BASED ON A PHENOTHIAZINE POLYMER DERIVATIVE AND YEAST ALCOHOL-DEHYDROGENASE FOR THE ANALYSIS OF ETHANOL, Biosensors & bioelectronics, 8(3-4), 1993, pp. 229-237
Amperometric biosensors for ethanol were constructed by immobilizing y
east alcohol dehydrogenase (ADH) on carbon paste (graphite powder: par
affin oil) chemically modified with a polymer to which a necessary med
iator for electrocatalytic NADH oxidation had been covalently attached
. Three different approaches were tested: adsorption of ADH on the ele
ctrode surface and adding NAD+ to the contacting buffer; having both A
DH and NAD+ mixed into the paste; and co-immobilizing ADH and NAD+ in
the paste by adding polyethylenimine to the reaction mixture. The last
approach resulted in the highest and fastest response. When inserted
into a flow injection system, the biosensor responded linearly to etha
nol between 2 muM and 3 mM. The biosensor operates at +100 mV vs. Ag/A
gCl.