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Poster Contributed Presentation

RAM

Monday Poster Sessions

M43 - Surfaced Enhanced Raman Spectroscopy for Nitrate Detection

Monday, October 6, 2025
9:45 AM - 5:30 PM EDT
Location: Ballroom C
In fifteen words or less, explain the significance of this contribution (Novel Aspect).: SERS is utilized for the improvement of nitrate detection in agricultural and environmental applications.

Abstract Text: Nitrate is a critical soil nutrient that plays an integral role in various avenues of plant metabolism. Both insufficient and excess nitrate can be detrimental to plant life in differing ways. Reliable quantification of nitrate is important for agriculture to ensure proper plant growth. However, nitrate detection in soil is difficult due to low concentrations, lengthy sample preparation, and extensive off-site analysis. Raman scattering, the inelastic scattering of light, yields molecularly specific analysis that is particularly well suited for nitrate detection. The Raman active vibrational modes in nitrate p</span>rovide a specific signal to identify and quantify this analyte in a complex environmental matrix. Raman spectroscopy is ideal for agricultural and biological applications as it offers insensitivity to water and rapid, in-field analyses. While Raman scattering is a low probability event, surface enhanced Raman spectroscopy (SERS) enhances the weak Raman signal by exploiting the localized surface plasmon resonance (LSPR) of noble metal nanoparticles. LSPR refers to the collective oscillation of electrons resulting in electromagnetic enhancement of the Raman signal from molecules near the metal surface. SERS provides the increased signal necessary to detect the low concentrations of nitrate present in soil. In the present work, we explore the use of gold nanoparticles (AuNPs) for SERS detection of nitrate. However, nitrate does not have an affinity for gold nanoparticles themselves, and therefore the use of ligands functionalized to the gold surface will be employed to attract nitrate. Ligands with an affinity for nitrate will encourage the necessary proximity of nitrate to the AuNP surface needed for detection. Our work optimizing the SERS signal includes selecting an appropriate affinity agent capable of significant enhancement. In addition, both spherical AuNPs and gold nanostars (AuNS) are utilized due to their distinct shape and tunable LSPR. AuNS exhibit areas of increased enhancement and have a higher LSPR closer to the 785nm laser used. Through optimization of particle size, shape, and ligand, nitrate signal is maximized. Increasing the sensitivity for nitrate in soil is a notable precursor to in-field detection for agricultural applications.