text: The EQCM sensitivity factor K can be calculated by combing the electrochemical cell measured charge density and QCM measured frequency shift. The sensitivity factor is only valid when the mass change on the electrode is homogenous. Otherwise, K is taken as the average sensitivity factor of the EQCM.
  where  is the measured frequency shift (Hz), S is the quartz crystal active area (cm), ρ is the density of quartz crystal,  is the quartz crystal shear modulus and  is the fundamental quartz crystal frequency. K is the intrinsic sensitivity factor of the EQCM.
  In a certain electrolyte solution, a metal film will deposited on the working electrode, which is the QCM sensor surface of QCM.
  The charge density () is involved in the electro-reduction of metal ions at a constant current , in a period of time  ().
  The active areal mass density is calculated by
  where  is the atomic weight of deposited metal, z is the electrovalency, and F is the Faraday constant.
  The experimental sensitivity of the EQCM is calculated by combing  and .