Determination of Pesticides in Tobacco Automated with FREESTYLE QuEChERS and LC-MS/MS

Significance of the Topic

Pesticide analysis in tobacco represents a critical challenge due to its complex matrix and significant matrix effects in mass spectrometry. High throughput and precise quantification of up to 220 pesticides are essential for regulatory compliance, quality control, and ensuring consumer safety. Automated clean-up approaches enhance reproducibility and reduce operator variability.

Objectives and Study Overview

This study aimed to integrate an automated non-dispersive QuEChERS clean-up using the FREESTYLE system with LC–MS/MS detection to streamline pesticide residue analysis in tobacco. A pesticide mixture of 220 compounds was evaluated to assess recovery, reproducibility, and matrix suppression.

Sample Preparation and Clean-up Methodology

Tobacco samples were homogenized and extracted with water and acetonitrile using QuEChERS-MIX I. The supernatant was subjected to an automated SPE clean-up on a specialized cartridge via the FREESTYLE QuEChERS platform, followed by direct injection into the LC–MS/MS system. This non-dispersive approach retains matrix interferences at the cartridge inlet, resulting in cleaner extracts.

Used Instrumentation

• FREESTYLE BASIC robotic platform with SPE module and HPLC Direct Injection interface
• Agilent Infinity II 1290 HPLC coupled to an API 5500 Triple Quadrupole MS/MS (ESI, positive mode)
• NUCLEOSHELL® Bluebird RP18 column (2.7 μm, 50 × 4.6 mm)

Main Results and Discussion

LC–MS/MS analysis demonstrated that 64 % of the 220 pesticides yielded recoveries within the 60–120 % target range with RSDs < 20 %. Some compounds experienced matrix-induced suppression or enhancement, which can be corrected using compound-specific factors. UV absorbance measurements between 200 and 800 nm confirmed significant removal of UV-active matrix components after automated clean-up, highlighting improved extract cleanliness.

Benefits and Practical Applications

The automated QuEChERS clean-up offers high reproducibility, reduced manual labor, and 24/7 unattended operation for up to 120 samples. Cleaner sample extracts minimize matrix effects in LC–MS/MS assays, enhancing data quality for routine pesticide monitoring in tobacco and potentially other complex matrices.

Future Trends and Opportunities

Advancements may include integrating real-time data analytics and AI-driven method optimization to further improve selectivity and throughput. Expanding the approach to additional challenging matrices, miniaturizing cartridge formats, and adopting greener solvents will support sustainable high-throughput residue analysis.

Conclusion

The automated non-dispersive FREESTYLE QuEChERS clean-up paired with LC–MS/MS provides a robust, reproducible, and high-throughput solution for comprehensive pesticide analysis in tobacco. This method reduces matrix interferences, improves analytical precision, and supports continuous routine operations.