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

Significance of the topic

Reliable multiresidue pesticide analysis in food is critical for consumer safety, regulatory compliance and trade. Modern monitoring requires sensitive, high‑throughput methods capable of screening hundreds of analytes in complex plant matrices that contain pigments and coextractives. Combining advanced triple‑quadrupole GC‑MS/MS hardware, flexible inlet technologies and automated software workflows addresses throughput, selectivity and operator variability challenges common in routine residue laboratories.

Objectives and overview of the study

This application study evaluated an integrated solution for simultaneous analysis of over 300 pesticide compounds in spinach extract. The approach couples a GCMS‑TQ 8040 RX triple‑quadrupole GC‑MS/MS with a Multi‑Mode Injection unit (MMI) operated in programmed temperature vaporization (PTV) mode. Method generation was automated via the Smart Pesticides Database (pre‑registered retention indices and MRM transitions), and AI‑assisted peak integration (Peakintelligence for GCMS) was applied to improve peak detection and reduce manual intervention. Quantitative performance, sensitivity (LOQ), linearity and repeatability were assessed using QuEChERS‑prepared spinach extracts and matrix‑matched calibration standards.

Methodology and sample preparation

Sample matrix: Spinach, chosen for its high pigment and coextractive content to challenge cleanup and quantitation.

Sample homogenization: Pre‑cooled dry‑ice grinding to minimize volatilization and degradation during homogenization.

Extraction & cleanup: QuEChERS workflow compliant with AOAC 2007.01. Extraction salts and dSPE cleanup kits (Restek Q‑sep kits) were used to standardize extraction and remove bulk interferences.

Calibration: Matrix‑matched standards were prepared by spiking blank extract to final concentrations of 0.1, 0.5, 1, 5, 10, 20, 50, 100, 200 and 400 ppb (for some compounds calibration was limited to 200 ppb). Recovery and repeatability were assessed at 10 ppb (n = 6).

Used Instrumentation

Key hardware and consumables reported:

• GC‑MS: Shimadzu GCMS‑TQ 8040 RX (triple quadrupole MS)
• Injection unit: Multi‑Mode Injection Unit (MMI‑U) capable of PTV and pulsed splitless modes
• Column: SH‑I‑5Sil MS (30 m × 0.25 mm I.D., 0.25 µm) with a 5 m guard/retention gap
• Liner: Xtra Inert Splitless liner
• Carrier gas: Helium, linear velocity control (~44.1 cm/s)
• Acquisition: Multiple reaction monitoring (MRM) on triple quadrupole MS
• Software: Smart Pesticides Database Ver. 2.2 for automated MRM method generation and LabSolutions Insight with Peakintelligence for GCMS for AI‑based peak integration

Representative analytical settings: 2 µL injection (pulsed injection at 250 kPa for 1.5 min), MMI PTV program from 60 °C rapid ramp to 300 °C, GC oven program with initial 70 °C to improve low‑boiling analyte peak shapes, loop time 0.4 s, sampling time 1 min.

Automated method development (Smart Pesticides Database)

The Smart Pesticides Database contains retention indices and up to six MRM transitions per pesticide for ~530 regulated compounds. Automated method generation uses measured n‑alkane retention indices and the database AART function to place expected analyte retention windows and select MRM transitions that minimize matrix interference—eliminating the need to measure individual pesticide standards to build the MRM list. The database thus accelerates multiresidue method setup and supports selective transition selection in complex matrices.

Role of MMI in PTV mode and advantages

Using the MMI in PTV mode (low inlet temperature at injection followed by rapid heating) allows temporary retention of solvent and analytes in the liner and subsequent controlled vaporization. Benefits observed:

• Suppression of thermal decomposition of thermally labile pesticides compared with conventional splitless injection
• Improved transfer efficiency for low‑boiling compounds when the GC initial temperature was lowered (70 °C)
• Enhanced overall sensitivity and peak shape in complex extracts

Data processing: Peakintelligence for GCMS

Peakintelligence is an AI‑based waveform processing algorithm trained to emulate experienced analysts’ peak detection and integration behavior. In side‑by‑side comparisons with conventional peak processing (Chromatopac), Peakintelligence provided more reliable integration for low‑concentration peaks, crowded chromatograms and elevated baselines, reducing manual corrections and operator variability.

Main results and discussion

Compound scope and linearity:

• 386 pesticides were evaluated; 357 compounds (~92%) showed excellent linearity with R² ≥ 0.995 across the tested calibration ranges.
• Calibration range typically 0.1–400 ppb (some compounds ≤ 200 ppb).

Sensitivity (LOQ distribution):

• 213 compounds (~60% of those with good linearity) were detectable at 0.1 ppb.
• The remaining compounds showed LOQs at 0.5 ppb, 1 ppb or >5 ppb depending on analyte and matrix effects.

Accuracy and precision in challenging matrix:

• Trueness values for many pesticides fell within the SANTE guideline acceptance range (70–120%), demonstrating acceptable recoveries despite the spinach matrix.
• Repeatability (%RSD) at 10 ppb (n = 6) was generally well below the common acceptance criterion of 20% for most compounds; a distribution showed substantial numbers in the <5% and 5–10% bands.

Key factors enabling results:

1. Triple‑quadrupole MRM acquisition for robust selectivity and sensitivity;
2. PTV injection to reduce thermal degradation and improve delivery of volatile analytes;
3. Automated transition selection to avoid matrix interferences;
4. AI‑based peak integration to reduce false positives/incorrect integrations and operator workload.

Representative calibration curves and chromatograms demonstrated near‑ideal linearity (R² values ~0.999 for several tested pesticides) and detectable chromatographic signals at or near LOQ levels.

Benefits and practical applications

Practical benefits of the integrated workflow for routine residue analysis:

• High‑throughput screening of hundreds of pesticides in a single GC‑MS/MS run;
• Automated method setup reduces development time and dependence on reference standards for initial retention placement;
• Improved quantitation reliability in complex matrices via selective transition selection and AI‑assisted integration;
• PTV inlet reduces thermal degradation, enabling analysis of thermolabile pesticides that might be underestimated with conventional injection;
• Overall improvement in laboratory efficiency, result confidence and reduced analyst bias.

Use cases: regulatory monitoring, QA/QC in food production, screening prior to confirmatory analysis, and high‑throughput contract testing labs.

Future trends and possibilities

Likely developments building on this work include:

• Expanded and curated spectral/MRM databases with broader regulatory coverage and real‑world matrix annotations;
• Tighter integration of AI across method development, automated QC flagging and decision support for analysts;
• Hybrid workflows combining high‑resolution MS for unknown identification with triple‑quadrupole quantitation for targeted screening;
• Increased adoption of large‑volume injection modes (LVI) and inlet automation to further boost sensitivity;
• Regulatory harmonization and cloud‑based method sharing to accelerate adoption and comparability across laboratories.

Conclusion

The study demonstrates that a combined platform—GCMS‑TQ 8040 RX with an MMI operating in PTV mode, automated MRM generation from the Smart Pesticides Database and AI‑assisted peak integration (Peakintelligence)—enables reliable multiresidue pesticide analysis in a challenging plant matrix. High linearity, low LOQs for many analytes, acceptable trueness and repeatability support the approach for routine monitoring. The integration of database‑driven method setup and AI processing reduces method development burden and operator variability, improving laboratory throughput and confidence in results.

References

Shimadzu Corporation. Simultaneous Analysis of Pesticide Residues in Food Using Triple Quadrupole GC‑MS/MS with PTV Mode of a Multimode Injection Unit (MMI). Application News, First Edition Jul. 2026. (Shimadzu Application News 01‑01233‑EN)