Electrode-separated piezoelectric quartz crystal and its application as a detector for liquid chromatography

The electrodes were removed from both surfaces of a piezoelectric quartz crystal and platinum electrodes were set on both sides of the crystal plate a few tenths of a millimetre apart. The spaces were filled with liquids. This system, called an electrode-separated piezoelectric quartz crystal (PQC), oscillation when the electrodes were connected to an oscillator, and the frequency varied with the density, viscosity and specific conductivity of the liquid like a normal piezoelectric quartz crystal having vacuum-evaporated metal electrodes, and the permittivity of the liquid also varied with mass change on the surface of the crystal plate in the liquid. The electrode-separated PQC was used as a detector for liquid chromatography.