Maintaining Sensitivity and Reproducibility with the Agilent JetClean Self-Cleaning Ion Source for Pesticides in Food and Feed

Importance of the topic

Monitoring pesticide residues in food and feed is critical for consumer safety and regulatory compliance. Complex matrices such as honey can deposit residual compounds in the ion source of a gas chromatograph, causing signal degradation and increasing maintenance time. A self-cleaning ion source introduces a controlled hydrogen flow to continuously remove deposits, thereby maintaining sensitivity and reproducibility while reducing instrument downtime.

Objectives and overview of the study

This application note evaluates the performance of the Agilent JetClean self-cleaning ion source on an Agilent 7010A Triple Quadrupole GC/MS system. Approximately 200 pesticides in organic honey extracts were analyzed with and without continuous hydrogen flow at 0.13 mL/min. The study compares chromatographic peak shape, baseline stability, linearity, method detection limits (MDLs), and reproducibility.

Methodology

Sample Preparation:

• Hydration and extraction of 5 g organic honey with water and acetonitrile using QuEChERS EN salts.
• Dispersive SPE (dSPE) cleanup followed by centrifugation to remove matrix interferences.

MRM Method Development:

• Selection of 195 target pesticides using the Agilent Pesticide & Environmental Pollutant Enhanced MRM database.
• Optimization of the top three transitions per compound with segment-specific dwell times for ~5 scans/s.

Data Analysis:

• Calibration over 0.12–50 ppb; calculation of MDLs from 10 replicates at 2.5 ppb with a 99 % confidence level.

Instrumentation

Key instruments and configuration:

• Agilent 7890B GC with 7693B autosampler and Multimode Inlet (splitless, 280 °C).
• Two 15 m × 0.25 mm DB-5ms Ultra Inert columns with post-run backflush via a purged union.
• Agilent 7010A Triple Quadrupole GC/MS with JetClean self-cleaning ion source.
• JetClean operation set to Acquire & Clean mode with continuous H₂ flow (0.13 mL/min) controlled by MassHunter software.

Main results and discussion

Continuous hydrogen flow improved chromatographic peak shape and baseline cleanliness for late-eluting, higher molecular weight pesticides. Linearity remained high (R² ≈ 0.99) both with and without JetClean. Average MDLs were lowered from 0.170 ppb (no JetClean) to 0.147 ppb (with JetClean). Reproducibility (%RSD) at 2.5 ppb showed comparable precision. A slight reduction in absolute signal was observed under continuous cleaning but did not compromise quantitation at regulatory-relevant levels.

Benefits and practical applications

• Extended intervals between manual source cleanings and reduced instrument downtime.
• Consistent sensitivity and reproducibility during long sequences of complex samples.
• Enhanced throughput for routine pesticide residue monitoring in food and feed laboratories.

Future trends and application opportunities

Further development may include adapting self-cleaning ion sources to a broader range of analyte classes, optimizing hydrogen flow rates for different matrices, and integrating automated maintenance routines across various mass spectrometry platforms. Such advances support high-throughput laboratories and strengthen quality assurance in environmental and food safety testing.

Conclusion

The Agilent JetClean self-cleaning ion source effectively maintains chromatographic performance and lowers detection limits for pesticide analysis in organic honey. Continuous hydrogen flow at 0.13 mL/min delivers improved peak shape and baseline stability, enabling reliable quantitation with reduced maintenance requirements.

References

1. K. A. Anderson et al. Modified ion source triple quadrupole mass spectrometer gas chromatograph for polycyclic aromatic hydrocarbon analyses. J. Chromatogr. A 1419, 89–98 (2015).
2. M. Anastassiades et al. Development of a QuEChERS sample preparation method for multi-residue pesticide analysis. AOAC Int. 86, 412–431 (2003).
3. S. J. Lehotay, K. Mastovská, A. R. Lightfield. Use of QuEChERS in pesticide residue analysis. J. AOAC Int. 88, 615–629 (2005).
4. J. Westland, J. Stevens. An optimal method for the analysis of pesticides in a variety of matrices. Agilent Technologies Application Note 5991-7303EN (2016).
5. Agilent Technologies. Pesticides and Environmental Pollutants Standard MRM Database User’s Manual G9250AA Rev. A.4.00, publication number G3445-90040.