3.6. Interferences
The selectivity of the microbial biosensor was studied on
some common organic compounds present in alcoholic beverages:
methanol, propanol, iso-propanol, acetic acid and
glucose. Measurements were performed with yeast cells immobilised
on a DM and on a PTFE membrane (TM), at
25 ◦C, pH 7 for concentrations of 0.5mM for each compound.
The results presented in Fig. 4 show that only glucose
interferes in the determination of ethanol. All the
volatile organic compounds do not interfere. A second anti-interference enzymatic layer based on GOD and CAT
is the usual way to eliminate the interference of glucose
for almost all kind of biosensors. In this case, the substrate
is a volatile compound and use of a gas-permeable membrane
represents the most convenient way to eliminate the
interference of glucose.
Using a PTFE membrane (TM) the microbial biosensor
responds selectively to ethanol in the presence of all the other
compounds tested. The use of this membrane affects the
response time of the biosensor. Independence from external
factors such as pH and contamination represent the main
advantages of separation of the biocatalytic layer from the
sample solution.
3.6. InterferencesThe selectivity of the microbial biosensor was studied onsome common organic compounds present in alcoholic beverages:methanol, propanol, iso-propanol, acetic acid andglucose. Measurements were performed with yeast cells immobilisedon a DM and on a PTFE membrane (TM), at25 ◦C, pH 7 for concentrations of 0.5mM for each compound.The results presented in Fig. 4 show that only glucoseinterferes in the determination of ethanol. All thevolatile organic compounds do not interfere. A second anti-interference enzymatic layer based on GOD and CATis the usual way to eliminate the interference of glucosefor almost all kind of biosensors. In this case, the substrateis a volatile compound and use of a gas-permeable membranerepresents the most convenient way to eliminate theinterference of glucose.Using a PTFE membrane (TM) the microbial biosensorresponds selectively to ethanol in the presence of all the othercompounds tested. The use of this membrane affects theresponse time of the biosensor. Independence from externalfactors such as pH and contamination represent the mainadvantages of separation of the biocatalytic layer from thesample solution.
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