Abstract

Surface-enhanced Raman spectroscopy (SERS) is used to detect catecholamines - viz., dopamine, norepinephrine, epinine, and isoproterenol - using a new substrate prepared with sol-gel technology. Catecholamines are complexed at the surface by iron(III) ions, which were introduced during the reduction of the silver ions embedded inside the sol-gel matrix. With the use of a He-Ne laser at a power of only 12 mW, it is possible to measure dopamine in the micromolar concentration range. A single-fiber SERS probe system was also introduced that has great potential for sampling in micro-environment applications such as <i>in vivo</i> measurements of dopamine. In this microprobe design both excitation and SERS signals are transmitted through the same fiber simultaneously. The tips of tapered fibers were coated with a polyvinyl alcohol polymer doped with metallic silver particles. The potential of the SERS method and microprobes for medical diagnostics is discussed.

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