Analysis of Pesticides by Supercritical Fluid Chromatography/ Mass Spectrometry

Importance of the Topic

Multi-residue pesticide analysis is essential for ensuring food safety, regulatory compliance and environmental protection. Supercritical Fluid Chromatography (SFC) provides higher separation speed and efficiency than traditional HPLC methods while maintaining comparable sensitivity. Coupling SFC to triple quadrupole mass spectrometry enables rapid, sensitive quantification of complex pesticide mixtures.

Objectives and Study Overview

This study aimed to develop and optimize a rapid SFC–MS/MS method for the separation and quantification of 17 pesticides in under five minutes. The method leverages the Agilent 1260 Infinity Analytical SFC system coupled to the Agilent 6460 Triple Quadrupole LC/MS. Key goals included reducing runtime, maximizing resolution, and achieving low limits of quantification.

Used Instrumentation

• Agilent 1260 Infinity Analytical SFC Solution (Control Module, Binary Pump, Autosampler, High-Performance Degasser, DAD, Thermostatted Column Compartment with Valve Drive)
• Agilent 6460 Triple Quadrupole LC/MS System with Jet Stream ESI Source
• Splitter Kit (50 µm × 100 mm capillary, backpressure regulator, solvent filter)
• Agilent 1260 Infinity Isocratic Pump for makeup flow
• ZORBAX Columns: NH2, Rx-SIL, SB-CN (4.6 × 150 mm, 5 µm)

Methodology and Instrumentation

An automated scouting wizard evaluated three column chemistries and organic modifiers (methanol, ethanol, isopropanol) with three gradient steepness profiles to achieve complete elution at ≤ 5 minutes. Final SFC conditions: CO2 flow 3 mL/min, 2→15→20 % methanol gradient in 5 min, backpressure 120 bar, column at 40 °C. Makeup solvent (acetonitrile + 0.2 % formic acid) was delivered via an isocratic pump with a flow gradient from 0.5 mL/min → 0.3 mL/min. MS/MS parameters were optimized in two stages: MRM transitions and collision energies with MassHunter MRM Optimizer, and source conditions (voltages, gas flows, temperatures) with MassHunter Source Optimizer.

Key Results and Discussion

The optimized method resolved 17 pesticides within a 5-minute runtime. Two near-coeluting pairs were distinguished by unique MRM transitions. Calibration was linear from 1 to 1000 ng/mL (R2 > 0.999). Limits of detection were < 1.6 ng/mL and limits of quantification < 2.9 ng/mL. System precision was high, with retention time RSD < 0.4 % and peak area RSD < 4 %. Makeup flow optimization balanced sensitivity across early and late eluters, and Jet Stream parameter tuning enhanced overall response.

Benefits and Practical Applications

• High-throughput screening of pesticide residues in food and environmental samples
• Significant reduction in analysis time compared to conventional HPLC
• Robust sensitivity and precision suitable for regulatory compliance
• Automated method development streamlines laboratory workflows

Future Trends and Opportunities

Integration of high-resolution MS detection with SFC, further automation of method optimization via AI-driven tools, and development of greener workflows using CO2-based mobile phases are anticipated. Miniaturized SFC systems and real-time monitoring solutions will expand SFC applications across industry sectors.

Conclusion

A robust SFC–MS/MS workflow for rapid multiresidue pesticide analysis was established, achieving excellent separation, sensitivity, and repeatability in a five-minute run. This approach offers a compelling alternative to traditional HPLC–MS/MS for routine pesticide screening in analytical laboratories.