Solid Phase Extraction of Pesticides from Fruits and Vegetables, for Analysis by GC or HPLC

Importance of the Topic

Solid phase extraction (SPE) enables efficient cleanup and concentration of pesticide residues in fruits and vegetables, meeting regulatory demands for food safety monitoring and reducing organic solvent consumption compared to traditional methods.

Objectives and Study Overview

This bulletin describes the development and validation of graphitized carbon black (ENVI-Carb) SPE cartridges for simultaneous cleanup and analysis of over 200 pesticide residues, including organochlorine, organophosphorus, nitrogen-containing, and carbamate compounds, with detection by gas chromatography–mass spectrometry (GC–MS) and high-performance liquid chromatography (HPLC).

Methodology

Pesticides were extracted from produce via acetonitrile homogenization, salt-induced phase separation, and drying, followed by cleanup on ENVI-Carb SPE tubes; elution used acetonitrile/toluene (3:1). Additional C18 or aminopropyl cartridges were optional for nonpolar or polar interferences. GC–MS was used for most pesticides; HPLC with post‐column derivatization and fluorescence detection was applied to carbamates.

Instrumentation Used

• ENVI-Carb SPE tubes (graphitized carbon black, nonporous, 40–100 µm)
• C18 and aminopropyl SPE cartridges for dual cleanup
• Visiprep vacuum manifold for parallel SPE processing
• GC–MS with capillary columns for target analytes
• HPLC UV detector with post‐column derivatization for carbamates

Main Results and Discussion

ENVI-Carb SPE tubes demonstrated improved recovery and precision for polar pesticides, achieving average recoveries of 95–98% for carbamates such as oxamyl, methomyl, and aldicarb versus 43–67% using C8/C18 silica tubes and 55–88% by liquid–liquid extraction. A broad comparison across more than 200 pesticides showed consistent recoveries (70–110%) in multiple matrices (banana, pear, pineapple, sweet potato, green pea), while charcoal/Celite minicolumns often failed to retain certain analytes. The carbon packing’s nonporous structure enabled rapid sample throughput without analyte diffusion losses.

Benefits and Practical Applications

• High recoveries and reproducibility for a wide range of pesticide chemistries
• Reduced solvent use and automated SPE for up to 24 samples simultaneously
• Elimination of labor‐intensive charcoal/Celite minicolumn preparation
• Flexible integration with C18 and aminopropyl cleanup steps for complex matrices
• Compatibility with routine GC–MS and HPLC workflows

Future Trends and Potential Applications

Emerging analytical needs may drive adaptation of ENVI-Carb materials for multiclass screening in high‐throughput labs, coupling with tandem mass spectrometry for lower detection limits, and miniaturized or on‐line SPE formats for rapid processing. Advances in carbon nanomaterials could further enhance selectivity and capacity.

Conclusion

Graphitized carbon black SPE tubes offer a robust, solvent‐saving alternative to conventional silica‐based and liquid–liquid methods, providing superior recoveries, simplified workflows, and adaptability for comprehensive pesticide monitoring in fruits and vegetables.

References

• Fillion J., Hindle R., Lacroix M., Selwyn J. Validation of Graphitized Carbon SPE for Multiresidue Pesticide Analysis. J. AOAC Int. 78, 1252–1266 (1995).
• Chaput D. Post‐column Derivatization Techniques for Carbamate Analysis by HPLC. J. AOAC 71, 542–546 (1988).