Simultaneous Analysis of Pesticide Residues in Food Using Triple Quadrupole GC-MS/MS with SPL Mode of a Multimode injection Unit (MMI)

Significance of the Topic

Gas chromatography coupled with triple quadrupole mass spectrometry (GC-MS/MS) is a cornerstone technique for multiresidue pesticide analysis in food. High-throughput monitoring is increasingly important for regulatory compliance and public health, but persistent challenges include complex matrices, inlet contamination from simplified extraction workflows (e.g., QuEChERS), frequent maintenance downtime, and the labor/time cost of method development and data processing. Advances in inlet design, automated method generation, and AI-driven data processing can materially improve productivity and reliability for routine pesticide screening and quantitation.

Objectives and Study Overview

• Demonstrate simultaneous multiresidue pesticide analysis in four challenging food matrices (spinach, orange, avocado, ginger) using Shimadzu GCMS-TQ 8040 RX equipped with a Multi-Mode Inlet (MMI).
• Showcase automated method creation using the Smart Pesticides Database (retention indices, multiple MRM transitions per compound) without requiring pesticide standards for retention alignment.
• Evaluate analytical performance (linearity, limits of quantification, and repeatability) for hundreds of pesticides and assess the practical benefits of MMI and AI-based peak processing (Peakintelligence for GCMS) in a high-throughput workflow.

Methodology

• Sample selection and preparation: four representative matrices known for diverse coextractives. Samples were cryogenically ground and extracted/cleaned up using a QuEChERS workflow (AOAC 2007.01) with commercially available extraction salts and dSPE tubes tailored per matrix.
• Calibration: multilevel standards in acetonitrile (0.1–400 ppb, some compounds up to 200 ppb) with an analyte protectant (AP) mixture added as a pseudo-matrix to reduce matrix effects.
• Automated method generation: Smart Pesticides Database (530 regulated pesticides) provides retention indices and up to six MRM transitions per compound; measuring n-alkanes and using automatic retention time alignment (AART) enables method construction without pesticide standards.
• Chromatography and MS acquisition: pulsed splitless injection (MMI in SPL mode), injection 2 µL, initial oven temperature modified to 70 °C to improve low-boiling pesticide peak shapes; MRM acquisition with 0.4 s loop time.
• Data processing: LabSolutions Insight for quantitation and Peakintelligence for GCMS (AI-based peak integration) to emulate expert peak handling without user-defined parameters.

Used Instrumentation

• Mass spectrometer: GCMS-TQ 8040 RX (Shimadzu)
• Injection unit: Multi-Mode Inlet (MMI-U) operated in pulsed splitless mode
• Column: SH-I-5Sil MS, 30 m × 0.25 mm, 0.25 µm; SH-I 5 m guard/retention gap column
• Liner: Xtra Inert Splitless liner
• Carrier gas: Helium with linear velocity control (44.1 cm/s)
• MS settings: ion source 230 °C, interface 280 °C, MRM acquisition
• Software and databases: Smart Pesticides Database, LabSolutions Insight, Peakintelligence for GCMS

Main Results and Discussion

• Matrix complexity: Total ion chromatograms (scan mode) for blank extracts revealed abundant coextractives across all four matrices (pigments, acids, lipids), highlighting potential interference with target MRM transitions.
• Analytical performance for standards: Of 386 pesticides evaluated, 362 (~94%) displayed excellent linearity (R² ≥ 0.99). Around 142 compounds (~39%) were detectable at 0.1 ppb under the calibration scheme with APs.
• Repeatability in standards: At 10 ppb (n = 6), 344 of 362 compounds (~95%) showed %RSD < 10% for peak area, indicating robust instrument and method stability.
• Matrix-spiked repeatability: For pesticide-fortified extracts at 10 ppb, more than 80% of evaluated pesticides achieved %RSD < 10% across the four matrices despite their complexity, demonstrating practical applicability for routine monitoring.
• Value of automated tools: The Smart Pesticides Database enabled rapid MRM method creation using retention indices and selectable transitions to avoid matrix interferences. Peakintelligence provided consistent peak integration comparable to experienced analysts without manual parameter tuning—critical when handling hundreds of MRMs in high-throughput settings.
• Operational benefit of MMI: The MMI’s fast heating/cooling and thermal insulation markedly reduced downtime associated with inlet maintenance (liner changes, temperature stabilization), improving instrument uptime compared with conventional split/splitless inlets while retaining method compatibility.

Benefits and Practical Applications

• Throughput: Combined improvements (MMI, automated method creation, AI peak processing) streamline method setup and sample throughput for laboratories handling large numbers of food samples.
• Maintenance efficiency: Reduced waiting time for inlet cooldown and re-stabilization increases productive instrument time and lowers operational disruption in routine workflows.
• Robustness for complex matrices: Selectable MRM transitions and AI-based integration mitigate matrix interferences, enabling reliable quantification across diverse food types.
• Regulatory and QC use: The workflow is directly applicable to routine residue monitoring, compliance testing, and QA/QC environments that require reproducible multi-residue analysis at low ppb levels.

Future Trends and Potential Applications

• Expanded curated databases: Broader, regularly updated retention-index and transition libraries will further reduce method development time and improve compound coverage globally.
• Deeper AI integration: Enhanced machine-learning models for deconvolution and identification could further reduce false positives/negatives in heavily coeluting regions and adaptively select optimal MRM transitions per matrix.
• Automation and sample-to-result workflows: Greater integration of sample prep robotics, inlet designs that tolerate higher matrix loads, and cloud-enabled data processing will enable scalable monitoring networks.
• Complementary detection strategies: In some use cases, pairing high-resolution MS for non-target screening with fast triple-quadrupole MRM workflows for confirmed quantitation will provide broader surveillance capability.
• Instrument design: Continued development of inlet materials and thermal control to minimize carryover and extend time between maintenance events.

Conclusion

This study demonstrates a practical, high-throughput GC-MS/MS workflow for multiresidue pesticide analysis that combines a Multi-Mode Inlet (MMI) to reduce maintenance-related downtime, automated method generation via a comprehensive Smart Pesticides Database, and AI-driven peak integration (Peakintelligence). The approach delivered strong linearity, low limits of quantification for many compounds, and good repeatability in both standards and challenging food matrices. Together, these advances support more efficient and reliable routine pesticide monitoring in food safety laboratories.

Reference

• Yamada K., Kawamura K. Simultaneous Analysis of Pesticide Residues in Food Using Triple Quadrupole GC-MS/MS with SPL Mode of a Multimode injection Unit (MMI). Shimadzu Application News, First Edition July 2026.