COMPARISON OF A PIEZOELECTRIC IMPEDANCE SENSOR-BASED FLOW-INJECTION SYSTEM AND A N,N,N',N'-TETRAKIS-2-HYDROXYLETHYL ETHYLENEDIAMINE-COATED QUARTZ-CRYSTAL MICROBALANCE FOR DETERMINATION OF CO2 IN WINE AND BEER

A novel FIA system for CO2 was constructed and compared with a N,N,N', N'-tetrakis-2-hydroxylethyl ethylenediamine(THEED)-coated quartz cryst al microbalance (QCM) for the determination of CO2 in wine and beer sa mples. This FIA method is based on the use of a gas-permeable membrane to separate CO2 from a carrier stream of 0.5 mol/l phosphate buffer ( pH 6.0) into a recipient stream of 10 mmol/l tris(hydroxymethylamino)m ethane (Tris) containing 1.0 mmol/l KCl and a piezoelectric impedance sensor to follow the conductance change occurring in the acceptor solu tion. Although the results for real samples obtained by the FIA, the Q CM and the conventional titrimetric methods, respectively, agree well with each other, the FIA method offers the best precision. The FIA met hod is also characterized by its high throughput, promising sensitivit y, excellent selectivity, low cost and easy manipulation, etc. The inf luence of some experimental parameters on the FIA's performance is dis cussed in detail.