Exploring the application of a universal method for pesticide screening in foods using a high data acquisition speed MS/MS

Importance of the Topic

Rapid and reliable pesticide screening in food is critical for safeguarding public health and meeting regulatory standards. High-throughput methods that cover a broad range of compounds without extensive method development can streamline quality control in agricultural products.

Objectives and Study Overview

This study evaluates a generic liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach for screening 172 pesticides in various food matrices. The aim was to apply high-speed multiple reaction monitoring (MRM) on a triple quadrupole instrument without compound-specific retention time scheduling.

Methodology and Instrumental Setup

Sample preparation followed a modified QuEChERS protocol:

• 5 g of homogenized sample mixed with water and acetonitrile for extraction.
• Salting out with NaCl and phosphate buffer, dehydration with anhydrous sodium sulfate.
• Cleansing via ENVI-Carb/LC-NH2 SPE with toluene/acetonitrile elution.
• Final extract dissolved in methanol for injection.

Chromatographic and mass spectrometric conditions:

• UHPLC system with Shim-pack XR-ODSII column, gradient elution using 5 mM ammonium acetate in water and methanol.
• Flow rate 0.2 mL/min, column at 40 °C.
• LCMS-8040 triple quadrupole MS with ESI in positive/negative modes.
• 344 MRM transitions (2 per compound) without retention time scheduling.
• High-speed acquisition: 5 ms dwell time, 1 ms pause time, 15 ms polarity switching.

Main Results and Discussion

The universal method successfully detected ten representative pesticides spiked at 10 ppb in leek, paprika, and green tea leaf extracts. All target compounds produced clear MRM peaks within a 20-minute run. Automated peak selection allowed identification without prior retention time information. False positive rates ranged from 7 to 10 across different matrices out of 172 screened compounds, demonstrating reasonable selectivity for an unscheduled approach.

Benefits and Practical Applications

• Single-method screening reduces development time and simplifies laboratory workflows.
• High-speed MRM enables coverage of large analyte lists within a standard run time.
• Automatic peak selection supports rapid data processing and reporting.
• Applicable to diverse food matrices with minimal method adjustments.

Future Trends and Potential Applications

Ongoing advances may include:

• Integration with high-resolution mass spectrometry for enhanced confirmatory analysis.
• Machine learning algorithms for improved false positive discrimination.
• Extension to environmental and biological samples for broader monitoring.
• Miniaturized sample preparation and on-site testing platforms.

Conclusion

The study demonstrates that an unscheduled, high-speed LC-MS/MS method can effectively screen a wide range of pesticides in food samples with satisfactory sensitivity and selectivity. This universal approach supports high-throughput quality control and regulatory compliance in food safety laboratories.