Sd. Sprules et al., A DISPOSABLE REAGENTLESS SCREEN-PRINTED AMPEROMETRIC BIOSENSOR FOR THE MEASUREMENT OF ALCOHOL IN BEVERAGES, Analytica chimica acta, 329(3), 1996, pp. 215-221
A disposable sensor strip was fabricated by a screen-printing procedur
e. This consisted of a Meldola's blue modified carbon working electrod
e and a Ag/AgCl combined reference/counter electrode printed alongside
each other on a PVC substrate. The working electrode was coated with
a mixture containing alcohol dehydrogenase (10 units) and NAD(+) (60 m
u g) to produce a sensor that would respond to alcohol. In order to im
prove the stability of the enzyme system the non-reducing sugar known
as trehalose was incorporated into the enzyme/cofactor coating. Withou
t trehalose the response to ethanol decreased dramatically over a peri
od of 21 days, and no detectable signal was detected on the last day.
With trehalose, 90% activity was observed 49 days after production. Us
ing amperometry in stirred solution a calibration graph exhibited line
arity up to a concentration of 35 x 10(-3) mol dm(-3) ethanol. The bio
sensor was used to determine the concentration of ethanol in a commerc
ial gin sample and good agreement was obtained between the calculated
value and that obtained by a recommended gas chromatographic procedure
. Butan-1-ol > propan-1-ol > propan-2-ol also gave responses.