Behavior of a Piezoelectric Quartz Crystal in an Aqueous the Application to the Determination of Minute Aniotint Solution and of Cyanide

Abstract

The frequency change of a piezoelectric quartz crystal is proportional to the weight of materials adsorbed on the electrode of the crystal in the air. It was found that the crystal oscillates when the one side of the electrode was in contact with the solution, and the frequency change (ΔF, Hz) of the crystal depended also upon the specific gravity (d) and the specific conductivity (k, Ω^-1·cm^-1) of the solution.
ΔF=2.87x 10³k^0.811-8.69×10³(d-1)^1.02, Hz
The frequency of the crystal was changed in proportion to the weight of the electrode, which could be dissolved through the reaction with the chemical species in the solution. Therefore the determination of the species, which reacted with the electrode, could be performed if the specific gravity and conductivity of the solution was kept constant. In this report, the principle was applied to the determination of cyanide ion in 0.01 moil/ boraxsodium hydroxide buffer solution (pH 9.60). Cyanide ion reacts with the silver electrode of the crystal and changes the frequency. The relation between frequency change (ΔF_CN, Hz)and cyanide concentration (M, mol/l) was formulated as ΔF_CN=46.5 x 10⁵M. Cyanide solution from 1 x 10^-6 to 5 × 10^-5mol/l was determined with the percent standard deviation of 2.16%for the 6 determinations of 2 x10^-5mol/l cyanide solution.