Abstract
In this paper, we investigate the potential of using quartz tuning fork (QTF) sensing system for detectionof specific metal ions in aqueous solutions with sample volume of 1 mu L. Functionalized self-assembledmonolayers (SAMs) of L-glutathione (LG) on gold-coated QTFs were used to sense specific analytes of CaCl2 and HgCl2, whereas functionalized L-cysteine based SAMs used to sense PbCl2. The resonance frequency undergoes a shift in response to the interaction between functionalized QTF and target analyte. X-ray photoelectron spectroscopy was used to study the interaction of thiol groups between the functionalized SAM and gold coated on QTF surface. Our analysis revealed that active QTFs functionalized with LG are more sensitive to detection of CaCl2 compared with HgCl2. The SAM-based QTF sensors were found to be capable of detecting low concentrations (10(-12) M) of divalent analyte solutes with high sensitivity.