Preparation and Application of Piezoelectric Crystal Ion Sensor Based on Silver Nanoparticles

[[abstract]]The application of nanomaterials in the field of chemical sensors has become a new,growing area of interest in recent years.Because nanomaterials features that differ from bulk materials. Because of their greater surface area compaired with bulk material, nanomaterials can be applied as efficient adsorbents in chemical sensor for detecting target analyte.A piezoelectric quartz crystal sensor based on coated silver nanoparticles was set up to study the interaction between silver nanoparticles and various metal cation. Silver nanoparticles were prepared by reduction of AgNO3 with NaBH4 in ice bath. Phase transfer of silver nanoparticles from aqueous to organic solutions using Octadecylamine (ODA) molecules as a surfactant. The partially irreversible response for cation was observed by desorption study,which implied that cation could be adsorbed on silver nanoparticlesby chemisorption. Effects of pH and interfering species on the responses of silver nanoparticles coated piezoelectric crystal sensor for cation was studied.Optimum pH was found to be at 8.03 . There were difference that silver nanoparticles interact with various cations in different organic solvents and interfering species.The much interference resulted in, the less response change of the piezoelectric crystal sensor of interaction.The detection limit of various cations were 4.78?10-6M for K+ ion, 6.78?10-6M for Mg2+ ion, 2.94?10-6M for Cu2+ ion, 4.71?10-6M for Zn2+ ion, 3.30?10-6M for Ni2+ ion, 7.7?10-7M for Cr3+ ion. Partical size of silver nanoparticles were measured by Transmission electron microscopy (TEM) and surface of coating silver nanoprticles on piezoelectric quartz crystalwas investigated by Scanning electron microscopy(SEM). The effects of cations on the absorption spectra of silver sols have been also investigated by the UV-VIS spectrometry.The interaction between silver nanoparticles and cations resulted in absorption wavelength red shift or blue shift and change in color of solution. In conclusion, silver nanoparticles-immobilized piezoelectric crystal sensor can be applied for study of the interaction between silver nanoparticles and cations.The ion PZ sensor for cations basedon silver nanoparticl was successfully to detect various cations.The PZ sensor for cations exhibited good selectiveity and detection limit in aqueous solution. Keyword: piezoelectric crystal sensor, silver nanoparticles, surfactant