Analysis of Captan, Folpet and their derivatives in food with APCI-LCMS-8060

Importance of the Topic

Captan and Folpet are phthalimide-based fungicides extensively employed in vineyards, cereal and vegetable crops. Their accurate quantification in food matrices is vital for consumer safety and regulatory compliance. Traditional GC–MS methods suffer from thermal degradation of these compounds, leading to unreliable results and low robustness.

Objectives and Study Overview

This study introduces a liquid chromatography–tandem mass spectrometry (LC–MS/MS) method with an atmospheric pressure chemical ionization (APCI) interface to analyze Captan, Folpet and their degradants (phthalimide and tetrahydrophthalimide) in food. The goal was to develop a sensitive, rapid and robust approach capable of achieving quantification limits below regulatory thresholds across diverse matrices.

Methodology

Sample preparation followed the QuEChERS EN 15662:2018 protocol with dSPE cleanup (PSA/C18). Calibration standards were prepared at 10 concentration levels ranging from 0.5 to 1000 ng/mL in acidified water (0.1% acetic acid) to stabilize analytes and optimize peak shape. Method validation included calibration linearity, limit of quantification (LOQ), repeatability and accuracy assessments in solvent and four food matrices (rice, apple, mikan and matcha tea).

Used Instrumentation

• Nexera X2 ultra-high-performance liquid chromatograph (Shimadzu)
• LCMS-8060 triple quadrupole mass spectrometer with APCI source (Shimadzu)
• Flow injection analysis for MRM transition optimization

Main Results and Discussion

Calibration curves for all four analytes exhibited excellent linearity (R² > 0.99). LOQs ranged from 0.1 ng/mL in solvent up to 30 ng/mL in complex matrices, depending on the compound. Accuracy fell between 90–110%, and matrix repeatability at the LOQ level showed relative standard deviations below 11% even in matcha tea. The 10-minute chromatographic run time supports high throughput.

Benefits and Practical Applications

This APCI-LC–MS/MS method offers a robust alternative to GC–MS for phytosanitary residues prone to thermal degradation. It ensures reliable quantification of Captan, Folpet and their byproducts at trace levels in various foods, addressing the needs of QA/QC laboratories, regulatory monitoring and research applications.

Future Trends and Potential Applications

Advancements may include multiplexing additional pesticides and degradants, integrating high-resolution MS for untargeted screening, and automation of sample preparation to further enhance throughput. The technique could expand to environmental and biological matrices for comprehensive phthalimide residue profiling.

Conclusion

The developed APCI-LC–MS/MS protocol on the Shimadzu LCMS-8060 platform demonstrates high sensitivity, accuracy and robustness for the analysis of Captan, Folpet, phthalimide and tetrahydrophthalimide in food. It overcomes GC–MS limitations and aligns with regulatory requirements for residue monitoring.

References

• Oppermann U., Moreau S., Toinon D. Analysis of Captan, Folpet and their derivatives in food with APCI-LCMS-8060. Shimadzu Europa GmbH and Shimadzu Corporation, 2023.
• European Parliament and Council. Directive 2007/5/EC of 12 February 2007 amending Annex I of Directive 91/414/EEC. Official Journal L 49, 20.2.2007.
• European Union Reference Laboratory for Pesticide Residues. Observation on Captan and Folpet LC method, Version 1.