Title:
Detection of Urea Using Surface- Enhanced Raman Spectroscopy Sensor Utilizes Gold- nanoseeds

Speaker:
N.A. Abdullah, N.A. Bakar, M.M. Salleh and A.A.Umar

Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia, 43600 Bangi- UKM, Selangor, Malaysia.
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Abstract:
Surface-enhanced Raman scattering (SERS) is a phenomenon that enhanced Raman spectrum signal of specific molecules as a result plasmonic effect of metal nanoparticles. The phenomenon is potentially be used as sensor to detect the presence of specific molecules. A SERS sensor system was developed; consists of light source to excite analyte molecules, a Raman probe, sensor chamber and a spectrophotometer as an analyzer system. A duplex fiber optic is used to transmit light from the source to the probe and from the probe to the spectrophotometer. The important part in the sensing system is SERS substrate consist of a nanostructured metallic surface such as gold nanoparticles. This presentation reports a study on application of a SERS sensor system to detect urea molecules. Gold-nanoseeds (AuNS) that were prepared by the first of two steps of the seed-mediated technique where the sizes of the nanoseeds were controlled through the heat treatment periods. It was demonstrated that gold-nanoseeds (AuNS) with the averages sizes of 15-20 nm can be utilized to enhance the Raman peaks intensities of urea molecules. The enhancement intensities of the Raman peaks are linear with the urea concentrations where the lowest urea concentration that was detected using AuNS from this study is 0.09 mg/ml.