Trace Detection of Pyrimethanil in Wine

Significance of the topic

Adequate monitoring of pesticide residues in wine is critical for consumer safety and regulatory compliance. Pyrimethanil, a commonly used fungicide in viticulture, poses potential health risks if present above permissible levels. Rapid, sensitive, and on-site detection methods enable timely quality control throughout the winemaking process.

Objectives and scope of the study

This study demonstrates a field-deployable Surface-Enhanced Raman Spectroscopy (SERS) method using the Metrohm Instant SERS Analyzer (Misa) for trace quantification of pyrimethanil in white wine. The goals were to develop a simple sample preparation, validate detection limits down to regulatory thresholds, and establish a rapid workflow suited for winery and distribution environments.

Methodology and instrumentation

The protocol involves liquid–liquid extraction of spiked wine samples with chloroform, phase separation, evaporation of the organic layer, and reconstitution in gold nanoparticle (Au NP) colloid with salt to enhance the SERS signal. Key experimental parameters:

• Analyzer: Misa Advanced with Orbital-Raster-Scan spectrograph
• Laser power: 5 (arbitrary units)
• Integration time: 10 s, averaged over 10 scans
• Au NP solution and 0.5 mol/L NaCl for nanoparticle aggregation

Main results and discussion

Baseline-corrected SERS spectra of pyrimethanil extracted from wine show clear characteristic peaks down to 100 ng/mL, well below the 5 µg/mL regulatory limit. Overlaid spectra confirm reproducible fingerprint patterns at each concentration. The use of gold colloids and minimal sample handling yields both high sensitivity and specificity.

Benefits and practical applications of the method

• Portability: On-site analysis without bulky lab equipment
• Speed: Complete extraction and measurement within minutes
• Cost-effectiveness: Minimal reagents and consumables
• Compliance: Detects residues at or below EU/US limits

Future trends and possibilities for use

Advances in nanoparticle engineering and SERS substrate design may further lower detection limits and broaden applicability to other agrochemicals. Integration with cloud-based data platforms could enable real-time monitoring across vineyard networks and distribution centers.

Conclusion

The Misa-based SERS method offers a robust, user-friendly approach for rapid detection of pyrimethanil in wine. Its high sensitivity, coupled with straightforward sample preparation, supports proactive quality assurance in viticulture and wine commerce.