In Situ Monitor the Adsorption of Triton X-100 on Quartz Surface by an Electrode-Separated Piezoelectric Sensor

In the configuration of an electrode-separated piezoelectric sensor (ESPS), the quartz crystal surface is in a direct contact with the liquid phase. The quartz surface can be hydrated to form silanol groups, which can adsorb nonionic surfactant Triton X-100 through hydrogen-bonding interaction between the silanol OH group and the ether oxygen atoms. The adsorption process of Triton X-100 on quartz crystal surface corresponds to a mass increase and can be monitored in situ by the ESPS device. And the adsorption densities and kinetics parameters can be obtained in the ESPS method. It was shown that the adsorption of Triton X-100 on quartz surface is reversible with respect to the dilution of bulk phase and can be analyzed using Langmuir model. The adsorption density and adsorption equilibrium constant decrease as pH rises. With increasing ionic strength, the adsorption rate constant and equilibrium constant increase slightly.