Identify More Pesticides Faster Using the Agilent High-Efficiency Source

Significance of the Topic

Reliable detection of pesticide residues at low concentrations is critical for food safety and environmental monitoring. Combining robust sample screening with high throughput supports regulatory compliance and protects public health by ensuring contaminants are identified rapidly and accurately.

Study Objectives and Overview

This work evaluates the performance improvements achieved by integrating the Agilent 5977B GC/MSD equipped with a high-efficiency source (HES) and Deconvolution Reporting Software (DRS) into an automated pesticide screening workflow. The main goals were to increase the number of detectable targets in a single run, reduce analysis time, and enable confident identification at sub-10 ng/g levels.

Methodology and Instrumentation

Sample preparation involved spiking tomato extract with over 200 pesticides at 10 and 100 ng/g, corresponding to 10 pg and 100 pg injected masses. Key elements of the analytical setup included:

• Agilent 7890 gas chromatograph with proprietary capillary flow backflush to shorten cycle time and suppress background.
• Agilent 5977B single-quadrupole MSD coupled to a high-efficiency ion source (HES) to boost ion production and sensitivity.
• Deconvolution Reporting Software (DRS) employing the NIST AMDIS engine and a locked retention-time pesticide library for automated peak deconvolution and matching.

Results and Discussion

Compared to the standard extractor source, the HES configuration markedly increased target detection. At the 10 ng/g level, no pesticides were confidently identified using the extractor source, whereas 38 targets were detected with the HES. At 100 ng/g, the HES yielded nearly twice the number of library-matched compounds versus the standard source. Detailed NIST hit distributions demonstrated improved first-hit matches and reduced false negatives. An illustrative case for flusilazole showed clear chromatographic and spectral deconvolution at a 10 pg injection, with an AMDIS match factor of 84 and robust library confirmation.

Benefits and Practical Applications

The combined GC/MSD-HES-DRS approach offers:

• Enhanced sensitivity enabling full-scan screening at regulatory threshold levels (10 ng/g).
• Expanded target scope through automated deconvolution and a comprehensive database.
• Faster turnaround and higher laboratory throughput due to reduced cycle time and streamlined reporting.

Future Trends and Possibilities

Emerging directions include expanding the retention-time-locked libraries to cover more emerging contaminants, integrating machine-learning algorithms for improved spectral interpretation, and applying similar high-efficiency source strategies to tandem MS systems for even greater selectivity and sensitivity.

Conclusion

The Agilent Pesticide DRS Screening GC/MSD Analyzer, when paired with the 5977B MSD and a high-efficiency source, significantly enhances pesticide screening capability. This configuration delivers reliable positive identification in full-scan mode at trace levels, accelerates reporting, and supports comprehensive monitoring in food and environmental laboratories.

References

1. NIST/EPA/NIH Mass Spectral Library (NIST 14) and AMDIS User’s Guide, NIST Standard Reference Database 1A, Version 2.2.
2. Wylie P. L. Screening for 926 Pesticides and Endocrine Disruptors by GC/MS with Deconvolution Reporting Software and a New Pesticide Library; Agilent Technologies Application Note 5989-5076EN, 2006.