Better Pesticide Analysis with Agilent J&W Ultimate Plus Tubing in an Inert Flow

Significance of the Topic

Trace-level determination of pesticides in food by gas chromatography–mass spectrometry (GC/MS) is critical for food safety and regulatory compliance. Active surface sites in the flow path can adsorb or degrade sensitive analytes, leading to poor peak shape, low sensitivity, and poor reproducibility. Enhancing inertness of flow path components is essential for reliable quantitation of challenging pesticides.

Objectives and Study Overview

The application note aimed to evaluate Agilent J&W Ultimate Plus deactivated fused silica tubing as a GC restrictor for mass spectrometry interface in comparison with a competitive premium-deactivated tubing. Key goals included:

• Assessing peak shape and signal response for a 20-compound pesticide checkout mixture.
• Comparing performance at different on-column loadings (10, 5, and 2 ng per compound).
• Demonstrating the tubing’s role in achieving an inert flow path for trace analysis.

Methodology and Instrumentation

An Agilent 7890A GC coupled to a 5975C MSD with triple-axis detector and an Agilent G4513A autosampler was used. A 20 m×0.18 mm DB-UI 8270D Ultra Inert column operated under splitless injection with helium carrier flow. Agilent Purged Ultimate Union connected the analytical column to restrictor tubing. The pesticide standard (20 compounds at 10 ng/µL) was injected at 10 µL, with additional dilutions to 5 and 2 ng/µL on-column. Full-scan MS data (50–550 amu) were collected after a solvent delay of 3.4 min.

Main Results and Discussion

Ultimate Plus tubing delivered sharp, symmetrical peaks and enhanced responses for all target pesticides compared with competing tubing. Total ion chromatograms at 10 ng on-column showed clear resolution of 20 analytes in under 21 min. Normalized peak areas at 5 and 2 ng demonstrated 10–60 % higher signal for most compounds with Ultimate Plus. Organophosphorus and organochlorine pesticides, prone to surface adsorption, exhibited especially marked improvements.

Benefits and Practical Applications

• Improved sensitivity and reproducibility for trace-level pesticide analysis.
• Faster method development due to easy restrictor changes without breaking MS vacuum.
• Reliable quantitation of reactive pesticides in food testing laboratories.

Future Trends and Opportunities

Ongoing advances in inert flow path materials will drive lower detection limits and higher throughput in pesticide analysis. Integration with automated sample preparation (e.g., QuEChERS) and tandem MS detection will further enhance selectivity and robustness. Emerging deactivation chemistries may extend benefits to other active analyte classes.

Conclusion

Agilent J&W Ultimate Plus deactivated fused silica tubing significantly enhances GC/MS analysis of a broad range of pesticides by providing an inert flow path that yields superior peak shape, sensitivity, and reproducibility compared to premium competitor tubing.

Instrumentation Used

• Agilent 7890A gas chromatograph
• Agilent 5975C mass selective detector (triple-axis)
• Agilent G4513A autosampler
• DB-UI 8270D Ultra Inert column, 20 m×0.18 mm, 0.36 µm
• Agilent Purged Ultimate Union

References

1. Wylie PL. Screening for 926 Pesticides and Endocrine Disruptors by GC/MS. Agilent Technologies Application Note, 5989-5076EN, 2006.
2. Usher K. Analysis of Pesticide Residues in Apple by GC/MS using QuEChERS Kits. Agilent Application Note, 5990-4468EN, 2012.
3. Zhao L, Broske AD, Mao D, Vickers A. Evaluation of Ultra Inert Liner Deactivation for Active Compounds by GC. Agilent Technical Overview, 5990-7380EN, 2011.
4. Agilent Technologies. Purged Ultimate Union. Technical Overview, 5991-1114EN, 2013.
5. Lynam K, Smith D. Organophosphorus Pesticides in Apple by GC/MS/FPD with a DB-35ms Ultra Inert Column. Agilent Application Note, 5990-7165EN, 2012.