biosensors; even dilution was required for maltose analysis in beer
samples.
The precision of the method was evaluated by injecting 10 replicates
of the standard maltose solution (1.0 mM) and standard deviations
(S.D) and variation of coefficient (c.v %) were calculated as
±0.051 mM and 4.4% for AG/PyOx/CHIT and ±0.023 mM and 1.75%
for AG/PyOx/CHIT–CNT biosensors.
Operational stability is an important consideration for immobilized
enzymes. Stability of biosensors was investigated at operational
conditions (in working buffer solution, 35 °C) for 5 h and 15% and 13%
decrease in biosensor responses for AG/PyOx/CHIT and AG/PyOx/
CHIT–CNT biosensors were observed. Since, PyOx was reported to be
very stable enzyme in previous works [30,33], this drop could be due
to the drop in AG activity at described conditions.
In addition, the shelf life of AG/PyOx/CHIT and AG/PyOx/CHIT–CNT
was tested during 20 days. Biosensors were stored at 4 °C when not in
use and no decrease in their responses was observed.