Measurement of the concentration of mercury vapour in air through a piezoresonance method

Abstract The piezosorption method is based on the dependence of the frequency of a vibrating piezoelectric quartz resonator on the weight of the electrodes. AT-cut quartz resonators are used as sensors at 14 MHz. The electrodes represent thin layers of gold, which are at the same time performing the function of a mercury sorption coating. Linear relationship are established between the frequency response of the measuring quartz resonator and the period of action of mercury vapour. These results give us the opportunity to calculate that the detection limit at a mercury concentration in air of 2×10 −5 g/m 3 , is 1 Hz/min. The calculated detection limit according to the 3σ-criterion is 3 × 10 −6 g/m 3 with a measurement period of 10 min. Results of the investigation show that piezoelectric resonators can be used as sensors for the detection of small concentrations of mercury vapour in air up to a threshold limit value of 10 −5 g/m 3 .