Identification of taste solutions and their binary mixtures using SH-SAW resonator-based taste sensor

A novel two-port resonator-based shear-horizontal surface acoustic wave (SH-SAW) sensor has been designed for liquid analysis. The device operates at a wireless ISM frequency of 434 MHz and is built on a 36deg YX LiTaO₃ piezoelectric substrate. It relies on a purely physical detection mechanism and it has been designed to function without the need for analyte-specific coatings. The sensor proved successful in identification of all six tastes: alongside the four classical tastes - saltiness, sweetness, sourness, and bitterness - test samples included solutions simulating the umami and metallic tastes. The taste sensor was also able to separate between samples of the same taste class (e.g. caffeine and quinine hydrochloride of the bitter class) as well as to detect and classify samples of the same substance with different concentrations. Furthermore, the potential to identify binary mixtures and separate them from original component solutions was tested and confirmed experimentally.