Developing nondestructive sensitive detection for smoke-exposure assessment in wine via advanced Raman spectroscopy.

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Environmental Science

Background:

• Climate change exacerbates wildfire smoke events, posing a significant threat to the wine industry.
• Accurate and timely analysis of smoke-tainted wine is crucial for quality control and economic reasons.
• Volatile phenols, such as guaiacol, are key indicators of smoke exposure in grapes and wine.

Purpose of the Study:

• To develop and validate a rapid, sensitive method for detecting guaiacol in wine.
• To explore the utility of surface-enhanced Raman spectroscopy (SERS) and femtosecond stimulated Raman spectroscopy (FSRS) for smoke taint analysis.
• To investigate methods for mitigating interference in complex wine matrices, particularly red wine.

Main Methods:

• Utilized SERS and FSRS techniques for enhanced spectral analysis of volatile phenols.
• Employed gold nanoparticles for SERS substrate development.
• Investigated solid-phase extraction with LiChrolut-EN resin and dichloromethane for sample cleanup.

Main Results:

• SERS and FSRS enabled lower detection limits for guaiacol compared to spontaneous Raman.
• Guaiacol was detected at the parts-per-billion level in synthetic wine and milligram-per-liter level in authentic wine.
• LiChrolut-EN resin chromatography effectively reduced interference in red wine samples.

Conclusions:

• SERS and FSRS offer a promising approach for rapid, sensitive, and non-destructive detection of smoke taint compounds in wine.
• Optimized sample preparation, including solid-phase extraction, is vital for accurate analysis in complex matrices.
• Further research into eluting solvents and optimized spectroscopic conditions could lead to significant advancements in smoke exposure evaluation for wine.