An electrochemical quartz crystal microbalance is employed for investigating the formation of inhibitory polyphenol layers on the surface of gold electrodes. The frequency-time profiles are indicative of the formation of a thin insulating polymeric layer that meets the rigid film requirement. and are in good agreement with the voltammetric response. Once access to the monomer is blocked, no further frequency change is observed. The passivation process is explored as a function of the specific phenolic compound. its concentration, and operational conditions. Comparison to the charge passed during the film deposition indicates that the efficiency of the polymerization process is dependent upon the phenol concentration. Valuable insights are also gained for the entrapment of glucose oxidase within the electrochemically grown polyphenol.