Abstract: Solution properties of the piezoelectric quartz crystal were studied using a transistorized oscillator. Frequency shift increases linearly with the increasing electrolyte concentration with a slope which is common for the electrolyte salts. Grounding the detection cell, it results 'in a wider linearity range. Anew frequency shift method has been developed for rapid determination of total electrolyte concentration in natural waters.

Key words: Piezoelectcic crystal, Frequency property, Electrolyte solution, Salt content in natural water