Developing a plasmon resonance sensor for heavy metal ion detection
- Pathum Thani, Thailand : Asian Institute of Technology, 2008
- 57 p. : illl.
- Thesis ; no. ME-08-02 .
- Asian Institute of Technology. Thesis ; no. ME-08-02 .
A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Microelectronics, School of Engineering and Technology
Thesis (M.Eng.) - Asian Institute of Technology, 2008
Heavy metals are widely used in many industr ial fields, for example, copper is used as conductor in electronic devices that is causing increasing environmental concerns. Nanotechnology is a promising discipline that shows promise to impact diverse fields including metal sensors. In order to test heavy metal contaminants in water, we report a novel strategy for using nanoparticles cappe d with polymers (chitosan, crosslinked chitosan, Poly Acrylic Acid (PAA), Poly sodium Styrene Sulfonate (PSS) and glutaraldehyde) for sensing the metal ions. Th e nearly monodispensed nanoparticle of gold was used for the metal ion sensing whic h were obtained by reducing 1 mM of HAuCl 4 with tri sodium citrate in 1:3 ratio. The polycationic nature of polymers utilized for sensing heavy metal ions enables attachment of negatively charged nanoparticles onto the polymers through electrostatic interactions. Use of polymer serves dual pur pose of providing sufficient steric hindrance ensuring stability of the colloid and also the functionalization of gold the nanoparticles for sensing. The well-documented chelating proper ties of chitosan and the sensitivity of the plasmon resonance in gold nanoparticles to agglomeration have been employed to detect low concentrations of heavy metals ions in water. A comparison of the optical absorption spectra of the colloidal suspension before and after exposure to metal ions is a good indicator of the concentration of the heavy meta l ions. In order to complete the chelation of the metal ions, about 1 hour was sufficient for the reaction in most of the cases, but for 0.5% PSS capped gold colloids, the reaction wa s completed within 5 10 minutes. The best sensitivity for copper ion, obtained from the optical sensors, is 200 ppb by using gold colloid capped 0.1% glutaraldehyde crosslinked chitosan. This simple metal ion sensor can be implanted in lab-on-chip type of applications for easier implementation.
Surface plasmon resonance Heavy metals Nanoparticles