Trace Detection of Carbendazim on Strawberries

Importance of the Topic

Rapid, sensitive detection of surface pesticide residues on fresh produce is critical for consumer safety and regulatory compliance. Carbendazim is a widely used fungicide with established toxicity risks, making an efficient on-site screening method essential for farmers, distributors and quality control laboratories.

Objectives and Scope of the Study

This application note presents a streamlined protocol for detecting carbendazim on strawberry surfaces using Metrohm’s portable Metrohm Instant SERS Analyzer (MISA). It demonstrates library creation, sample preparation, spectral acquisition and field-deployable testing procedures to enable reliable, trace-level analysis outside a central laboratory.

Methodology and Instrumentation

The study employs surface-enhanced Raman spectroscopy (SERS) with gold nanoparticles. Key components include:

• MISA Advanced system featuring Orbital-Raster-Scan technology and Class 1 laser attachments
• ID Kit – Au NP containing colloidal gold, disposable spatulas, pipettes and vials
• Solvents and reagents: ethanol for rinsing, NaCl solution (500 mmol/L), glass beakers for sample collection

Experimental parameters such as laser power (5 mW), integration time (1 s), number of averages (10) and raster scan activation ensure reproducible spectra.

Main Results and Discussion

A reference SERS spectrum for pure carbendazim in methanol was established using Au nanoparticles. Field-mimicking samples (strawberries sprayed with 100 mg/L carbendazim) produced rinse extracts that, when mixed with Au NP and NaCl, yielded baseline-corrected spectra matching the reference. This confirms the method’s sensitivity and specificity for detecting carbendazim at agriculturally relevant concentrations.

Benefits and Practical Applications of the Method

Key advantages include:

• Portability: lightweight analyzer and rugged case enable on-site testing at farms, markets or processing facilities
• Speed: total analysis time under 10 minutes from rinse to result
• Sensitivity: trace-level detection supports compliance with strict international residue limits
• Versatility: adaptable workflow for other pesticides, fungicides and contaminants

Future Trends and Potential Applications

Emerging developments could include:

• Expanded nanoparticle chemistries for broader analyte coverage
• Integration with cloud-based spectral libraries and AI algorithms for automatic identification
• Miniaturized sample preparation modules for fully automated field workflows
• Regulatory acceptance and standardization of SERS-based pesticide screening

Conclusion

The MISA SERS approach provides a robust, user-friendly solution for rapid detection of carbendazim on fresh produce surfaces. Its portability and high sensitivity make it an effective tool for safeguarding food quality throughout the supply chain.

Reference

Metrohm AG. Application Note AN-RS-022: Trace Detection of Carbendazim on Strawberries with MISA. 2023.