Portable, handheld instrumentation is driving the development of applications of Raman spectroscopy in a variety of industries. Analytical applications of Raman requiring lower detection limits typically rely on surface enhanced Raman scattering (SERS). Thus, the combination of handheld instrumentation and SERS can be valuable for on-site sensing and monitoring. It follows that the development of field deployable SERS substrates will be crucial to these types of applications.<br/><br/>Our primary focus is to develop water dispersible SERS substrates for simple and rapid on-site analyses of water soluble analytes. In-solution SERS analysis is not as common as that performed on planar substrates, but has been reported using aggregated spherical particles or anisotropic shaped particles. In this work we investigated the SERS capability of gold nanostars as a dispersible SERS substrate using a handheld Raman spectrometer. The nanostars were synthesized using Good’s buffers and were optimized based on buffer choice, buffer to gold ratio, and with and without salt aggregation. Our analyses demonstrated reproducible detection of ciprofloxacin, thiabendazole and malachite green in under 5 minutes. Moreover, we developed a SERS assay to quantify methimazole, an anti-thyroid drug, in urine as a potential clinical application.<br/><br/>Our substrate demonstrates good long term storage and is easily deployed as a sensitive SERS substrate for rapid analyses. The merging of a handheld Raman spectrometer with gold nanostars provides a feasible field deployable SERS analysis platform.

Colloidal gold nanostars as a SERS substrate for the detection of methimazole in urine using a handheld Raman spectrometer

2019 Fall National Meeting

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