New workflow for contaminants screening in strawberries using high-resolution GC/Q-TOF and expanded accurate mass library of pesticides and environmental pollutants

Significance of the Topic

Strawberries are prone to pesticide residues and environmental pollutants, requiring analytical methods that deliver both high sensitivity and broad compound coverage. High-resolution GC/Q-TOF coupled with an extensive accurate mass library addresses these needs by improving detection capabilities and ensuring regulatory compliance.

Objectives and Study Overview

This study presents a streamlined workflow for simultaneous screening and quantitation of over 1000 pesticides and pollutants in organic and non-organic strawberry samples. The approach complies with SANTE guidelines and demonstrates enhanced data review flexibility.

Methodology

Sample preparation utilized the EN QuEChERS extraction followed by dSPE cleanup tailored for fruits and vegetables. Chromatographic separation was performed on an Agilent GC with mid-column backflush and a 40-minute retention time locked method. Analytical measurements were carried out in full scan mode on both high-resolution Q-TOF and single quadrupole mass spectrometers.

Instrumentation

Key instruments and parameters

• GC system: Agilent 8890 with HP-5MS UI columns (15 m × 0.25 mm, 0.25 µm)
• Injection: 1 µL pulsed splitless via MMI inlet at 280 °C
• Oven program: 60 °C (1 min); 40 °C/min to 120 °C; 5 °C/min to 310 °C
• Mass spectrometers: Agilent 7250 Q-TOF (45–650 m/z, 5 Hz) and 5977 MSD (45–550 m/z, 2.9 Hz)
• Data processing: MassHunter Quantitative Analysis with accurate mass PCDL for screening

Key Results and Discussion

Comparison of GC/Q-TOF with GC/MSD revealed

• Higher number of detected pesticides per sample, particularly in low-level organic extracts
• Typical detection of 10–20 pesticides in non-organic samples, including flonicamid, pyrimethanil, cyprodinil and others
• Minimum detected concentrations of 1.2 ppb for compounds such as cyprodinil and p,p′-DDE
• Identification of environmental contaminants including extractables, flame retardants and disinfectants
• Reduction of false positives and negatives demonstrated by examples such as cyprodinil quantitation and ethiofencarb interference identification

Benefits and Practical Applications

The workflow offers

• Compliance with regulatory MRL requirements
• Enhanced sensitivity and compound coverage
• Streamlined data review with accurate mass confirmation
• Reduced risk of misidentification compared to unit mass screening

Future Trends and Applications

Advancements may include expanding compound libraries, applying the workflow to diverse food matrices, integrating machine learning for automated suspect screening, and developing real-time monitoring platforms.

Conclusion

The demonstrated high-resolution GC/Q-TOF workflow combined with an accurate mass library provides a robust and flexible solution for pesticide and environmental contaminant screening in strawberries, improving sensitivity, specificity and data review efficiency.