Surface-Enhanced Raman Spectroscopy for Quantitative Nicotine Analysis in Dissolution Samples from Oral Tobacco-Derived Nicotine Pouches

Oral tobacco-derived nicotine (OTDN) pouches represent a rapidly growing segment in the smoke-free nicotine market. Positioned between the gum and lip, these products deliver nicotine via the oral mucosa, with release rate serving as a critical performance metric. Accurate quantification of nicotine release is essential for product development, manufacturing optimization, and regulatory evaluation. While liquid chromatography (LC) remains the industry standard for analyzing nicotine in dissolution fractions, this study introduces a novel approach for the determination of nicotine using surface-enhanced Raman spectroscopy (SERS). SERS offers distinct advantages, including high sensitivity and selectivity, rapid analysis, minimal sample preparation, and potential for real-time monitoring. Nicotine is inherently SERS-active, whereas common pouch excipients are not, enabling clear spectral identification with minimal interference. In this exploratory study, a small-volume sinker-type dissolution setup was employed to generate dissolution samples from various OTDN pouches under different dissolution experimental conditions. Gold nanostructures fabricated on filter paper served as the SERS substrate, and aliquots collected during dissolution were analyzed using a Raman system with a 3 mm laser illumination diameter to ensure representative and reproducible spectra. Nicotine concentrations in the dissolution fractions ranged from 2150 to 15600 µg/g. Surface-enhanced Raman spectroscopy (SERS) demonstrated robust capabilities in quantifying nicotine across all fractions, enabling the construction of dissolution release profiles for comparative analysis between products. This work highlights the potential of SERS to complement traditional chromatographic methods and advance analytical capabilities in nicotine product evaluation.