GC-MS/MS Pesticide Analysis in Green Tea in a Single Acquisition Using Xevo TQ-GC

Importance of the Topic

Tea is among the most widely consumed beverages globally and ensuring its safety requires sensitive and selective pesticide analysis. Green tea presents a complex matrix with many co-extractives that can interfere with targeted detection, making robust analytical workflows critical for regulatory compliance and consumer protection.

Objectives and Study Overview

• Develop a streamlined single-acquisition method for GC-MS/MS analysis of over 200 pesticides in green tea.
• Demonstrate concurrent acquisition of multiple reaction monitoring (MRM) and full-scan data using RADAR technology.
• Assess method performance against regulatory criteria for trace-level pesticide detection.

Methodology and Instrumentation

The sample preparation combined a DisQuE QuEChERS CEN extraction with Oasis PRiME HLB solid phase extraction pass-through cleanup. Matrix-matched calibration curves and QC samples were prepared in green tea extract. Instrumental analysis employed a Waters Xevo TQ-GC system with the following configuration:

• Injection: 1 µL splitless mode, electron ionization at 70 eV.
• GC conditions and MRM transitions automatically generated via Quanpedia database.
• Concurrent acquisition: MRM for targeted quantitation and full-scan (m/z 50–650, 0.5 s scan time) using RADAR technology.
• Data processing managed through MassLynx software and TargetLynx Application Manager.

Main Results and Discussion

• Calibration curves for 1–100 ppb in tea matrix (equivalent to 0.005–0.5 mg/kg) exhibited R2 ≥0.998, ion ratio deviation within ±30% and residuals below 20%.
• QC recoveries at 10 and 50 ppb (0.05 and 0.25 mg/kg) met acceptance criteria with concentrations within ±15% of target and precision (RSD) below 16%.
• RADAR full-scan data enabled identification of natural co-extractives such as caffeine and 1,2,3-benzenetriol by NIST library matching.
• Comparison of dedicated MRM versus MRM+full-scan showed signal retention between 56% and 97%, indicating minimal sensitivity loss while gaining full-scan information.

Benefits and Practical Applications

• Automated method setup via Quanpedia reduces development time and transcription errors.
• Concurrent MRM and full-scan acquisition supports both quantitative analysis and interference monitoring in a single run.
• Workflow meets regulatory requirements for trace pesticide analysis in complex matrices like green tea.
• Retrospective data mining capability enhances confidence in results and facilitates identification of unexpected co-extractives.

Future Trends and Opportunities

Further applications may include expanding RADAR-enabled workflows to other challenging food matrices, integrating advanced library search tools, and applying high-throughput automation for large-scale monitoring programs. Advances in data analytics and machine learning could enhance retrospective data mining for emerging contaminants.

Conclusion

The described Xevo TQ-GC workflow delivers robust, sensitive, and efficient single-acquisition pesticide analysis in green tea. Through automated method generation and RADAR technology, laboratories can achieve regulatory compliance, mitigate matrix interferences, and gain valuable full-scan data without compromising sensitivity.

Reference

• Hayward D et al (2015) J Agri Food Chem 37:8116–8124
• Cody R (2018) J Am Soc Mass Spectrom 29:1594–1600