Simultaneous Quantification of Pesticide Residues in Olive Oil via LC-MS/MS and GC-MS/MS Using a Streamlined, Automatable cSPE Clean-up Workflow

Significance of the Topic

Ensuring the safety of olive oil is critical as it is consumed worldwide. Pesticide residues pose health risks and must comply with EU maximum residue limits. This study addresses the need for accurate, high-throughput monitoring of over 200 pesticides in olive oil.

Objectives and Overview of the Study

The study aims to develop and validate a simultaneous quantification method for pesticide residues in olive oil using LC-MS/MS and GC-MS/MS coupled with an automatable cSPE cleanup workflow. Collaboration between Shimadzu and Biotage seeks to streamline sample preparation and meet SANTE guidelines.

Methodology

Sample Preparation:

• 5 g olive oil + 10 mL acetonitrile, vortex and centrifuge.
• 1 mL supernatant processed via dispersive SPE using Biotage ISOLUTE AOAC Waxed cSPE.
• Automated cleanup with Biotage Extrahera Classic to reduce manual variability.

Chromatographic Analysis:

• LC-MS/MS on Shimadzu LCMS-8045RX with Shim-pack Velox Biphenyl column; gradient elution with water/methanol containing 2 mM ammonium formate and 0.01% formic acid; ESI positive/negative.
• GC-MS/MS on Shimadzu GCMS-TQ8050 NX with Rtx-5MS column; splitless injection; helium carrier; programmed oven temperature.

Calibration and Validation:

• Matrix-matched external standards: 1–100 µg/L for LC, 5–200 µg/L for GC.
• Weighted regression (1/C or 1/C²), linearity R² ≥ 0.99.
• Spike recovery at 10 µg/kg, recoveries 70–120%, RSD < 20%, meeting SANTE criteria.

Used Instrumentation

• Shimadzu LCMS-8045RX with LC-40 series.
• Shimadzu GCMS-TQ8050 NX.
• Biotage Extrahera Classic automated SPE unit.

Main Results and Discussion

The method achieved high linearity and sensitivity across analytes. Representative chromatograms for fipronil and metalaxyl demonstrated clear separation and accurate quantification. Automated cSPE significantly improved reproducibility and throughput, reducing operator-dependent variability.

Benefits and Practical Applications

The validated workflow enables routine monitoring of over 200 pesticide residues in olive oil with minimal hands-on time. Automation enhances data quality and consistency, making it suitable for research, quality assurance, and regulatory compliance laboratories.

Future Trends and Potential Applications

• Integration of robotics and high-throughput platforms for larger sample loads.
• Extension of the workflow to other food matrices such as oilseeds and fats.
• Leveraging advanced databases and AI-driven data analysis for rapid screening.

Conclusion

The combined LC-MS/MS and GC-MS/MS approach with automated cSPE cleanup provides a robust, efficient, and compliant solution for pesticide residue analysis in olive oil.

Reference

1. Hakme E., Uclés S., Parrilla-Vázquez P., Gamón M., Cutillas V., Fernández-Alba A.R. Development and validation of a new multiresidue method for the determination of multiclass pesticide residues using GC-QqQ-MS/MS in edible oils.