A Blind Study of Pesticides in Vegetables by Agilent Bond Elut QuEChERS Extraction Kits and Agilent 5975T LTM GC/MSD

Importance of the topic

Monitoring pesticide residues in fruits and vegetables is essential to ensure food safety and regulatory compliance. Rapid, onsite analysis minimizes delays, supports emergency response, and protects consumers from harmful exposure.

Objectives and study overview

• Assess the performance of a portable Agilent 5975T LTM GC/MSD combined with Bond Elut QuEChERS extraction kits for pesticide detection in cherry tomato and cucumber matrices.
• Conduct a blind study by spiking 59 pesticides at concentrations from 0.05 to 1.0 µg/g to evaluate screening, identification, and quantitation capabilities.
• Demonstrate the use of Agilent DRS software and the RTL pesticide library for rapid, automated compound deconvolution and reporting.

Methodology and instrumentation

• Sample preparation followed a QuEChERS workflow: 5 g homogenate, water addition, acetonitrile extraction, salt packet (MgSO₄, NaCl, citrate salts), and dispersive SPE cleanup (PSA, C18, MgSO₄).
• GC/MS analysis employed the Agilent 5975T LTM GC/MSD with an HP-5ms LTM column (30 m × 0.25 mm, 0.25 µm) and a 1 m LTM guard column, splitless injection, helium carrier gas, and a temperature program from 70 °C to 280 °C.
• Automated liquid sampling was performed using the Agilent 7693 autosampler.
• Data acquisition and processing utilized Agilent GC/MS ChemStation, MSD Deconvolution Reporting Software (DRS), the RTL pesticide library, and NIST08 with AMDIS for spectral matching.

Main results and discussion

• Recovery tests at 0.05, 0.1, and 0.5 µg/g showed 79–118% recoveries with good repeatability.
• Calibration curves for all analytes were linear (R² > 0.995) over 0.05–0.5 µg/mL.
• DRS screening identified all 59 pesticides within 2–3 minutes per run; ChemStation quantitation confirmed approximately 95% of targets after database optimization.
• DRS detected several low-level residues below ChemStation quantitation limits, enhancing sensitivity for trace analysis.
• The replaceable LTM guard column effectively reduced matrix contamination, extending the main column’s operational life.

Benefits and practical applications

• Enables rapid, onsite pesticide screening without transporting samples to a central laboratory.
• Streamlines sample preparation with QuEChERS, reducing solvent use and handling time.
• Provides laboratory-grade accuracy and sensitivity in a mobile format.
• Delivers automated qualitative and semi-quantitative results for large pesticide panels, facilitating compliance testing and quality control.

Future trends and potential applications

• Expansion of pesticide and emerging contaminant libraries to include metabolites and new chemistries.
• Integration with cloud-based data platforms for real-time reporting and remote decision support.
• Development of more compact and automated field-deployable GC/MS instruments.
• Extension of the workflow to other food matrices, environmental samples, and forensic applications.

Conclusion

The combination of QuEChERS extraction, the portable Agilent 5975T LTM GC/MSD, and Agilent DRS software establishes a fast, reliable workflow for onsite multi-residue pesticide analysis in vegetables. High recoveries, strong linearity, and rapid screening support enhanced food safety monitoring and timely decision-making.