Fast Screening and Quantification of Pesticide Residues in Baby Food Using GC-Orbitrap MS Technology

Significance of the topic

Ensuring the safety of baby food requires sensitive, reliable analytical methods to detect trace levels of pesticide residues in complex matrices. High-resolution mass spectrometry (HRMS) coupled with gas chromatography offers a powerful approach for broad‐scope screening and accurate quantification while maintaining high throughput in routine laboratories.

Objectives and study overview

The primary goal was to evaluate the performance of a GC-Orbitrap MS system (Thermo Scientific™ Q Exactive™ GC) for rapid full-scan screening and quantification of 132 pesticides in baby food. Key performance metrics—sensitivity, mass accuracy, resolution, reproducibility and quantitative linearity—were assessed under fast chromatography conditions typical of high-throughput workflows.

Methodology and instrumentation

Sample preparation followed a citrate-buffered QuEChERS protocol. Final extracts (1 g/mL in acetonitrile) were spiked at 0.5–100 ng/g (and 1–200 ng/g for select analytes). GC separation was achieved on a TRACE™ 1310 GC with a TraceGOLD™ TG-5SilMS capillary column (30 m × 0.25 mm × 0.25 μm) using a PTV splitless injector. The Q Exactive GC Orbitrap MS acquired full-scan data at 60,000 FWHM (m/z 200) over 50–750 m/z, with an internal lock mass to maintain sub-ppm mass accuracy. Data processing and compound reporting utilized TraceFinder™ software.

Main results and discussion

• Chromatographic performance: Fast GC gradients produced narrow peaks (<2.5 s); the Orbitrap system recorded >15 scans/peak, supporting reliable peak integration.
• Sensitivity and detection limits: Instrumental detection limits (IDLs) for 95% of pesticides were ≤1 ng/g; all IDLs fell below EU maximum residue levels (0.01 mg/kg).
• Mass accuracy and selectivity: Sub-ppm mass errors (average ~0.4 ppm) across peaks eliminated isobaric interferences and increased confidence in compound identification.
• Quantitative linearity and precision: Calibration curves in matrix showed R² >0.99 over 0.5–100 (or 1–200) ng/g, with residuals <25% and repeatability (%RSD) of ~6%.
• Comparative performance: Sensitivity and quantitation were comparable to a triple quadrupole GC-MS/MS instrument (Thermo Scientific™ TSQ™ 8000 Evo), with 91% of compounds achieving IDLs <2 ng/g.

Benefits and practical applications

The GC-Orbitrap MS workflow enables broad-scope, full-scan pesticide screening at trace levels with high confidence, reducing false negatives and eliminating the need for targeted methods. Its fast scan speed, high resolution and mass accuracy support high throughput analysis in QA/QC and research settings, with performance on par with triple quadrupole systems.

Future trends and potential applications

• Expansion to non-targeted and retrospective data mining for emerging contaminants.
• Integration with automated sample preparation and robotic platforms for higher throughput.
• Development of advanced software tools for improved library searching and data visualization.
• Application to diverse food matrices, environmental samples and metabolomics studies.

Conclusion

The Thermo Scientific Q Exactive GC Orbitrap MS system delivers rapid, high-resolution full-scan analysis for pesticide residues in baby food, combining excellent sensitivity, sub-ppm mass accuracy and robust quantitative performance. It offers a versatile solution for broad-scope screening and quantification comparable to conventional MS/MS, streamlining laboratory workflows and enhancing data confidence.

Reference

1. Commission Regulation (EU) No 396/2005 on maximum residue levels of pesticides.
2. SANCO/12571/2013 Guidance on analytical quality control and validation for pesticide residues.
3. Commission Directive (EU) No 2003/13/EC amending processed baby food MRLs.
4. Thermo Scientific Application Note 10432: Fast Triple Quadrupole GC-MS/MS for Pesticide Residue Analysis in Baby Food.