Analysis of Pesticides in Food Matrix using QuEChERS by Triple Quadrupole GC/MS/MS and LC/MS/MS

Importance of the topic

Ensuring food safety by monitoring pesticide residues is a global challenge. Different countries set distinct maximum residue limits (MRLs) and analytical requirements, requiring fast, reliable, and sensitive methods. The QuEChERS approach coupled with triple quadrupole GC/MS/MS and LC/MS/MS enables comprehensive screening of hundreds of pesticide compounds in various food matrices, supporting regulatory compliance and protecting public health.

Objectives and overview of the study

This work evaluates the performance of Shimadzu’s GCMS-TQ8030 and LCMS-8040 instruments for analyzing 138 priority pesticides recommended by the European Union Reference Laboratory (EURL). Of these, 66 compounds are targeted by GC/MS/MS and 72 by LC/MS/MS. The study applies a unified QuEChERS pretreatment to leek and paprika samples, then assesses sensitivity, selectivity, linearity, repeatability, and recovery for all analytes.

Methodology

The QuEChERS procedure comprises:

• Extraction: Homogenization of 10 g sample followed by addition of 10 mL acetonitrile and a salt mixture (MgSO₄, NaCl, citrate salts), vigorous shaking, and centrifugation.
• Cleanup: Transfer of extract to dispersive SPE tube containing MgSO₄, PSA, and graphitized carbon (ENVI-Carb), followed by shaking, centrifugation, dilution, vortexing, and filtration.

Samples of leek and paprika extracts, spiked at trace levels (1–10 ppb), were analyzed under MRM mode to evaluate method performance.

Instrumentation used

The following systems and conditions were employed:

• GC/MS/MS: GCMS-TQ8030 with Rxi-5Sil MS column, splitless injection, helium carrier gas, and MRM acquisition using EURL-recommended transitions.
• LC/MS/MS: LCMS-8040 coupled to a Nexera UHPLC, Shim-pack XR-ODS II column, electrospray ionization with polarity switching, and 276 MRM transitions (dwell time 5 ms, pause time 1 ms).

Main results and discussion

GC/MS/MS analysis of 66 pesticides achieved detection limits below 1 ppb with signal-to-noise ratios exceeding 20. MRM mode outperformed SIM by rejecting matrix interferences and providing higher sensitivity. Repeatability tests (n=6) at 10 ppb spike levels yielded relative standard deviations below 1.5% for all compounds. LC/MS/MS analysis of 72 pesticides demonstrated linear calibration (1–1000 ppb, r²>0.999), detection at 1 ppb, and recoveries between 80% and 90% in both leek and paprika. A few analytes showed recoveries above 120% due to matrix background, but their quantitation remained below regulatory MRLs.

Benefits and practical applications of the method

The combined use of QuEChERS with triple quadrupole GC and LC systems offers:

• High sensitivity and selectivity for a broad spectrum of pesticides in complex food matrices.
• Rapid sample preparation and analysis, improving laboratory throughput.
• Robust performance with excellent repeatability and reliable quantitation relevant to regulatory monitoring.

Future trends and possibilities of use

Advances may include further miniaturization and automation of sample prep, expanded pesticide libraries to address emerging compounds, integration with high-resolution mass spectrometry for non-target screening, and harmonization of methods across global regulatory bodies. Improved dwell and polarity switching speeds will enable even larger multi-residue panels without compromising sensitivity.

Conclusion

This study confirms that the QuEChERS method, when paired with the GCMS-TQ8030 and LCMS-8040 platforms, provides a streamlined, high-throughput solution for simultaneous analysis of 138 pesticides. The combination delivers outstanding sensitivity, reproducibility, and compliance with EURL recommendations, making it well-suited for modern food safety laboratories.

References

1. European Union Reference Laboratory. Multiresidue method using QuEChERS followed by GC-QqQ/MS/MS and LC-QqQ/MS/MS for fruits and vegetables. EURL Analytical & Measuring Instruments Division, Shimadzu Corporation, 2012.
2. Shimadzu Corporation. Multi-class pesticides analysis in challenging vegetable matrices using fast 5 msec MRM with 15 msec polarity switching. IMSC 2012 Poster No. PO-CON1216E.