Surface plasmon resonance sensor : detection of heavy metal ions
- Pathum Thani : Asian Institute of Technology, 2012
- 1 online resource (62 p.) : ill.
- Thesis ; no. ISE-12-56 .
- Asian Institute of Technology. Thesis ; no. ISE-12-56 .
A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Nanotechnology, School of Engineering and Technology
Thesis (M. Eng.) - Asian Institute of Technology, 2012
Surface Plasmon resonance (SPR) based heavy metal ions sensor is one of the most sensitive sensor for detecting toxic metal ions. It is an inexpensive, portable and alsofeasiblefor real time detection. SPR sensor is a type of optical sensor in which toxic metal ions get adsorbed on the functionalized metal(mostly Au) film causes the change in refractive index of the metal (Au)-dielectric (sensing) medium.The change of the refractive index leads to a shift in the angular spectrum of the reflected light and can be accurately monitored by optical methods.In this dissertation,diffractive optical coupling element (DOE) was used for input and output coupling of light to excite the surface plasmon wave. In this SPR system, one DOE couples the input light beam and focus to the bottom of a sensing surface and the second DOE reflects the output beam to the CCD (charge-coupled devices) camera. Diffractiveoptical elements play a vital role to reduce the complexity of the SPR setup system.The diffractive optical elements werefabricated by nanoimprint lithography process. The sensor surface(gold film)was functionalized with crosslinked chitosan and applied the electric field (DC) to accumulate metal ions into the chitosan matrix. This combined method enhanced the adsorption of metal ions onto the SPR surface due to chelate properties of amine group as well asappliedelectric potential.The proposedsensor can be detected in the ppbrange (less than 10 ppb) of heavy metal ions such as Pb2+and Cd2+.Thus, diffractive optical elements embedded highly sensitive metal ions sensor has a potential to overcome the drawbacks of SPR sensor available today.