Analytical Sciences

Comparison of a Piezoelectric Impedance Sensor-Based Flow-Injection System and a N, N, N', N'-Tetrakis-2-hydroxylethy Ethylenediamine-Coated Quartz Crystal Microbalance for Determination of CO2 in Wine and Beer

Xiao-Li SU, Hu-Wei TAN, Wei-Feng LI, Wan-Zhi WEI and Shou-Zhuo YAO *

Chemical Research Institute, Hunan Normal University, Changsha 410081, P. R. China

A novel FIA system for CO2 was constructed and compared with a N, N, N¡þ, N¡þ-tetrakis-2-hydroxylethyl ethylenediamine(THEED)-coated quartz crystal microbalance (QCM) for the determination of CO2 in wine and beer sam-ples. 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)methane (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 QCM and the conventional titrimetric methods, respectively, agree well with each other, the FIA method offers the best precision. The FIA method is also characterized by its high throughput, promising sensitivity, excellent selectivity, low cost and easy manipulation, etc. The influence of some experimental parameters on the FIA's performance is discussed in detail. (Keywords: Flow injection analysis, piezoelectric impedance sensor, quartz crystal microbalance, carbon dioxide, wine, beer)

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