Abstract: A piezoelectric sensor responsive to vitamin B₁ was fabricated based on the vitamin B₁-tetraphenylborate ion pair. The general performance characteristics of the sensor are presented here. The proposed sensor showed a wide working pH range, a good sensitivity and selectivity. The response range is between 1.0×10^-7-4.9×10^-5 mol/L with a detection limit of 8×10^-8 mol/L at pH 4.0. The selectivity should be attributed to the preferential adsorption of the component ion on the membrane/solution interface. The adsorption behavior of vitamin B₁ on the crystal surface was investigated with a quartz crystal impedance(QCI) system.

Key words: Piezoelectric sensor, Vitamin B₁, Ion-pair complex