DEXTech Method Optimisation

Importance of the Topic

The determination of dioxins and PCBs in environmental and food samples is essential due to their high toxicity, environmental persistence and potential for bioaccumulation. Reliable, efficient sample preparation methods are critical for routine monitoring, regulatory compliance and risk assessment.

Objectives and Study Overview

This application note describes optimized automated extraction and clean-up protocols for dioxin and PCB analysis using the DEXTech system. Two column formats (Standard and SMART) are evaluated to minimize process time and solvent usage while maintaining analytical performance. The study also explores the reuse of carbon columns for cost savings.

Methodology and Instrumentation

The DEXTech automated sample preparation platform employs two types of glass columns packed with carbon and silica phases:

• Standard column: designed for common matrices
• SMART column: intended for samples with lower matrix load or reduced sample weight (up to 1.5 g)

Each protocol includes conditioning steps with toluene, dichloromethane/n-hexane and n-hexane, followed by sequential elution of four fractions: non-dioxin-like PCBs, mono-ortho PCBs, non-ortho PCBs and PCDD/Fs.

Main Results and Discussion

Key performance improvements compared to previous methods:

• Standard column: total run time reduced to 60 min and solvent consumption to 400 mL
• SMART column: run time reduced to 50 min and solvent use to 300 mL
• Reusing carbon columns for up to 20 cycles yields ~30 % cost reduction without loss of sensitivity or risk of cross-contamination

Fraction profiles confirm efficient separation of target analyte classes with indicator elution ensuring reproducibility.

Benefits and Practical Applications

The optimized DEXTech methods offer:

• Higher sample throughput for environmental, food and feed labs
• Reduced solvent waste and operational costs
• Robust performance across diverse matrices
• Scalability through optional column reuse

Future Trends and Applications

Emerging directions include integration of greener solvents, miniaturized column formats for further solvent reduction, AI-driven method optimization and expansion to additional persistent organic pollutants. These innovations will support faster decision-making in regulatory monitoring and research.

Conclusion

The optimized Standard and SMART column protocols on the DEXTech system significantly improve time efficiency and reduce solvent consumption while preserving analytical reliability for dioxin and PCB determination. Column reuse strategies further enhance cost-effectiveness without compromising data quality.