Rinse and Shoot: Rapid Pesticide Screening Workflow by GC/MS in Under Five Minutes

Significance of the Topic

The analysis of trace pesticides on fruit surfaces is critical for food safety and regulatory compliance. Rapid, reliable methods help mitigate public health risks and enable high sample throughput in food quality testing.

Objectives and Study Overview

This work presents a rinse and shoot workflow using gas chromatography with single quadrupole mass detection for screening of surface pesticides in under five minutes. The study evaluates sample preparation, analysis speed, and identification confidence.

Methodology and Instrumentation

Sample preparation involved rinsing fruits such as strawberry, lemon, banana, cherry, and peach with acetone into amber vials for direct injection. Chromatography was performed on an Agilent Intuvo 9000 GC equipped with a 10 m HP-5MS UI column and a 1.3 m deactivated fused silica restrictor, with an oven ramp of 250 °C per minute to yield a 3.4 minute run time. Backflushing was used to remove high boilers and extend column life. The detector was an Agilent 5977B single quadrupole MSD operated in full scan. Data analysis used MassHunter Unknowns Analysis with spectral deconvolution and time filtering via linear retention indices, supported by custom and commercial libraries of over 1,000 entries for automatic compound identification.

• Agilent Intuvo 9000 GC with PSD Module and MMI guard chip
• Agilent 5977B MSD
• HP-5MS Ultra Inert column and restrictor
• 7650A Automatic Liquid Sampler
• MassHunter Unknowns Analysis software

Main Results and Discussion

The method enabled detection of multiple pesticides including fenhexamid in strawberry rinsates within 3.4 minutes. Retention index calibration with an n-alkane ladder allowed robust matching independent of chromatographic variables. Screening across various fruits demonstrated rapid identification, while slower confirmation runs improved library match scores. System robustness was validated over 210 peach injections with minor maintenance restoring performance.

Benefits and Practical Applications

• High throughput screening in under five minutes per sample
• Minimal sample preparation with rinse and shoot
• Reliable identification using spectral deconvolution and retention indices
• Extended uptime via backflushing and guard chip protection

Future Trends and Opportunities

Advances may include expanded spectral libraries, integration with targeted quantitative assays, automated data processing, and application to other complex matrices. Coupling with high resolution instruments and machine learning could further enhance sensitivity and specificity.

Conclusion

The described workflow delivers rapid and reliable pesticide screening on fruit surfaces, combining minimal sample prep, fast GC/MS analysis, and robust identification techniques. It supports quick decision making for quality control and regulatory compliance.

Reference

1. Andrianova A et al Agilent Technologies Application Note publication 5994 0915EN 2019
2. Churley M et al Agilent Technologies Application Note publication 5994 1505EN 2019