DEVELOPMENT OF AN ALCOHOL OPTODE MEMBRANE-BASED ON FLUORESCENCE ENHANCEMENT OF FLUORESCEIN DERIVATIVES

A new type of optode membrane for the determination of alcohols, such as methanol, ethanol, propan-1-ol and propan-2-ol etc, is presented th at can be exploited in optical and fibre-optic sensors. It is based on the use of a new lipophilic fluorescent reagent, namely fluorescein o ctadecyl ester (FODE). which is immobilized in a plasticized PVC membr ane. The response mechanism relies on the fact that FODE can reversibl y recognize alcohol molecules due to the hydrogen bonding formation be tween FODE and alcohol molecules. The analytical information in this m embrane is the enhancement of the relative fluorescence intensity meas ured at 527 nm (463 nm, excitation). Under the optimum condition, the membrane has a wide measuring range for alcohol samples. The membrane has been applied to determine the concentration of ethanol in alcoholi c drinks with satisfactory results.