Analysis of Fruit and Vegetable Pesticides by GC/MS/MS Using Agilent Inert Flow Path

Significance of the topic

The accurate and precise measurement of trace-level pesticides in fruits and vegetables is critical for food safety, regulatory compliance, and public health. Surface inertness throughout the GC flowpath minimizes adsorption and degradation of reactive or polar analytes, enabling reliable quantitation at low parts-per-billion levels.

Objectives and Study Overview

This work systematically evaluates the Agilent Inert Flow Path (IFP) on GC/MS/MS for the multiresidue analysis of 32 pesticides in six matrices. Key objectives include

• Determining calibration linearity and method limits of quantitation
• Comparing Agilent IFP performance against non-Agilent inert components
• Validating an autosampler sandwiched injection approach for online matrix spiking
• Assessing the benefit of analyte protectants on method robustness

Methodology and Instrumentation

Sample preparation followed the AOAC QuEChERS protocol using acetonitrile with 1 % acetic acid and dispersive SPE cleanup. Calibration standards (2–200 ng/mL) and matrix-matched QCs were injected via an Agilent 7693 autosampler using two- or three-layer sandwiched injection to combine standards with matrix or reagent blanks inline.

Instrumentation details

• Agilent 7890A GC with UltiMetal split/splitless inlet, Ultra Inert gold seal, and wool-packed Ultra Inert liner
• Agilent 7000 Series triple quadrupole GC/MS/MS in MRM mode with retention time locking and backflush enabled
• Capillary Flow Technology Purged Ultimate Union and UltiMetal flexible ferrules

Main Results and Discussion

All 32 pesticides achieved a 2 ng/mL LOQ with excellent calibration linearity (R² > 0.99) across six matrices (strawberry, orange, plum, onion, red pepper, spinach). The Agilent IFP delivered higher signal responses and sustained peak integrity over extended sequences compared to non-Agilent components. Notable findings:

• QC recoveries of 80–120 % with RSD < 15 % for most analytes
• Enhanced durability and reduced signal decay for labile compounds (e.g., chlorothalonil, omethoate, acephate)
• Sandwiched injection simplified matrix-matched calibration preparation and minimized human error

Benefits and Practical Applications of the Method

The combined use of Agilent IFP, GC/MS/MS, and sandwiched injection offers:

• Superior inertness to prevent analyte loss and degradation
• High sensitivity and selectivity to meet stringent regulatory limits
• Robust handling of QuEChERS extracts through backflush enabled flowpaths
• Streamlined workflow by online matrix spiking, reducing benchwork and preparation time

Future Trends and Potential Applications

Emerging directions in pesticide residue analysis include:

• Broader adoption of online matrix spiking and sandwiched injection for diverse food matrices
• Fully inert GC flowpaths tailored for ultra-trace and highly labile analytes
• Hybrid screening combining GC/MS/MS and LC/MS/MS to cover a wider residue profile
• Automated addition of analyte protectants to further enhance method robustness

Conclusion

This evaluation confirms that the Agilent Inert Flow Path paired with GC/MS/MS and innovative sandwiched injection delivers a highly inert, sensitive, and reliable platform for multiresidue pesticide analysis in fruits and vegetables, outperforming conventional inert components and simplifying calibration workflows.

Reference

• Anastassiades M, Lehotay SJ. AOAC Int. 86, 412 (2003).
• Zhao L, Mao D. Agilent Application Note 5990-7706 EN (2011).
• Zhao L, Meng C-K. Agilent Application Note 5990-9317 EN (2011).
• Lynam K, Smith D. Agilent Application Note 5990-8235 EN (2012).
• Zhao L, Meng C-K. Agilent Application Note 5991-1196 EN (2012).
• Zhao L. Agilent Application Note 5991-1860 EN (2013).
• Meng C-K. Agilent Application Note 5990-9453EN.
• Szelewski MJ, Quimby B. Agilent Application Note 5989-1716EN.
• Meng C-K. Agilent Application Note 5989-6018EN.
• Giarrocco V, Quimby B. Agilent Application Note 5966-2469EN.
• Mastovska K. Agilent Reference Guide 5991-2389EN (2013).
• Lynam K. Agilent Application Note 5991-2745EN (2013).
• Mastovska K, Lehotay SJ, Anastassiades M. Anal. Chem. 77, 8129 (2005).