Multimethod Pesticide Analysis with the Agilent 1260 Infinity II Prime LC System and Agilent Ultivo Triple Quadrupole LC/MS

Significance of the Topic

Pesticide residues in food and agricultural products are strictly regulated to safeguard consumer health and comply with environmental standards. Reliable multiresidue analysis is essential to detect trace levels of diverse compounds and to verify compliance with maximum residue limits.

Objectives and Study Overview

This study evaluates the performance of the Agilent 1260 Infinity II Prime LC system coupled to the Agilent Ultivo triple quadrupole mass spectrometer for comprehensive pesticide screening. Key aims include assessing chromatographic separation, detection sensitivity, linear dynamic range, and recovery in a challenging green tea matrix.

Instrumentation Used

• Agilent 1260 Infinity II Flexible Pump (up to 800 bar)
• Agilent 1260 Infinity II Multisampler and Multicolumn Thermostat
• Agilent Ultivo LC/TQ mass spectrometer
• Agilent InfinityLab Poroshell 120 EC-C18, 2.1×100 mm, 1.9 μm column

Methodology

Chromatographic separation was achieved using a high-pressure sub-2 μm column at 30 °C with a ternary gradient of aqueous and organic modifiers. The flow rate was 0.35 mL/min and 1 μL was injected. Sample preparation followed a QuEChERS protocol involving water/acetonitrile extraction, salt partitioning, dispersive cleanup, and reconstitution prior to analysis. The MS was operated in dynamic MRM mode with optimized source conditions, acquiring over 500 transitions with dwell times around 5.6 ms.

Main Results and Discussion

More than 250 pesticide analytes were separated with minimal coelution. Critical isomer pairs such as phosphamidon I and II achieved a chromatographic resolution of 0.66. Most compounds exhibited linear calibration (R2>0.999) from 100 ppb down to 100 ppt, with lower limits of quantification below 100 ppt for over 86% of targets. Recoveries in spiked green tea ranged between 80 and 120% for the majority of analytes, meeting international guidelines. The high-pressure LC system effectively handled viscous methanol gradients, and a postrun column flush minimized carryover.

Benefits and Practical Applications of the Method

This workflow delivers high throughput and sensitivity for regulatory screening, enabling simultaneous quantification of hundreds of pesticides in complex matrices. The combination of sub-2 μm column technology and dynamic MRM enhances selectivity and reduces matrix interference, supporting quality control in food safety laboratories.

Future Trends and Potential Applications

Advances in column materials and ultrafast gradients may further reduce run times. Integration of automated sample preparation, high-resolution MS, and data analytics using machine learning will expand capabilities for comprehensive contaminant profiling and real-time decision support.

Conclusion

The Agilent 1260 Infinity II Prime LC system paired with the Ultivo TQ demonstrates robust performance for multiresidue pesticide analysis, achieving excellent sensitivity, resolution, and recovery. This approach supports stringent regulatory requirements and enhances confidence in food safety testing.

References

1. Regulation EC No 396/2005 on maximum residue levels of pesticides in food and feed.
2. Agilent Application Note 5991-3728EN: Optimizing Sample Preparation for LC/MS/MS of Pesticides Residues in Herbal Teas.
3. European Commission SANTE/12682/2019: Method Validation and Quality Control Procedures for Pesticide Residues Analysis.