SURFACE CHEMICAL ACTIVATION OF QUARTZ-CRYSTAL MICROBALANCE GOLD ELECTRODES - ANALYSIS BY FREQUENCY CHANGES, CONTACT-ANGLE MEASUREMENTS AND GRAZING ANGLE FTIR

Abstract

A hydroxyalkanethiol, HS(CH2)12OH was deposited onto the gold electrodes of quartz crystal microbalances and gold-coated quartz microscope slides in order to aid in subsequent immobilization of antibodies. FTIR and contact angle measurements confirm the presence of thiol on the fresh gold substrates. In contrast, the change in frequency of the quartz crystal during thiol adsorption indicates an apparent decrease in mass rather than the expected increase due to thiol coverage of the surface. This anomalous behavior appears to be partly due to the removal of organic contaminants from the "aged" gold surface by solvent action. In addition, there may be some dissolution of gold by the thiol solu..