An improved holder for the electrochemical quartz crystal microbalance and its cyclic voltammetry characteristics

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Abstract
The design and characteristics of a stationary, compact holder for an electrochemical quartz crystal microbalance (EQCM) are presented. A Au/quartz crystal oscillator is vertically mounted in a polytetrafluoroethylene body of the holder. The crystal is sealed with an O‐ring and is easily accessible for change. The performance of the holder was tested under cyclic voltammetry (CV) conditions with the Ag+ /Ag and Cu+ /Cu electrodeposition/electrodissolution processes. Frequency changes due to mass changes of the Au/quartz electrode were correlated with CV parameters. The holder was calibrated for a 5 MHz crystal oscillator by means of CV anodic stripping of silver. The mass sensitivity was 19.5 ± 0.1 ng Hz−1 cm−2. The concentration sensitivity was 14.2 ± 0.2 μM Hz−1 cm−2 at a potential scan rate of 0.01 V s−1 and 23.7 ± 0.3 μM Hz−1 cm−2 at a scan rate of 0.02 V s−1 for a potential of scan reversal which was 250 mV more negative than the electrodeposition peak potential.