| Summary: | 碩士 === 國立成功大學 === 材料科學及工程學系 === 106 === The presence of trace amounts of pesticides in agricultural products for human consumption has gained increasing concerns regarding the health risks they pose due to their neurotoxic nature. One of the sensitive and rapid detection methods that has been developed for quality control of these products is surface-enhanced Raman scattering (SERS) since it requires minimal to no sample preparation. In this study, a SERS-active substrate was fabricated wherein thermally evaporated gold nanoparticles (Au NPs) were deposited onto an ordered porous ZrO2 (pZrO2) layer that was produced through sol-gel method with an assisting template of polystyrene nanoparticles. With an optimized substrate-laser wavelength combination and Rhodamine 6G (R6G) as the probe molecule, an enhancement factor (EF) of 7.0 x 107 was obtained. The presence of hot spots in Au-Au interparticle gaps and the formation of electromagnetic fields on the Au-ZrO2 interfaces due to charge transfer between Au and ZrO2 are major factors that contribute to the SERS effect; in addition, the concave nature of the pores allowed the incident light to scatter in a way that it lead to further overlap of the electromagnetic fields. The substrate also exhibited homogeneity in terms of SERS measurements owing to its ordered morphological features. Furthermore, Au/pZrO2 substrates were also able to detect pesticides i. e. phosmet and carbaryl, down to low concentrations (0.3 ppm and 0.2 ppm, respectively). Multiplex detection of the pesticides was also demonstrated but with a selectivity to phosmet as its phosphoric groups has a strong affinity to ZrO2 aside from the affinity of its sulfur constituent to the Au component of the substrate. The Au/pZrO2 substrate has thus demonstrated a high potential in the rapid detection of trace amounts of pesticide.
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