Increase Throughput and Recoveries for EPA Method 508.1 with Automated Extraction using Strata® C18-E SPE Cartridges and Zebron™ ZB-MultiResidue™ GC Columns

Significance of the Topic

Chlorinated pesticides and organohalides pose persistent health and environmental risks, requiring sensitive and reliable analysis in water matrices. EPA Method 508.1 is a regulatory standard for monitoring these contaminants. Automating sample preparation and concentration enhances throughput, precision, and reduces resource consumption.

Objectives and Study Overview

This study evaluates an automated extraction workflow combining Strata C18-E solid phase extraction cartridges with Horizon Technology’s SmartPrep™ and DryVap® systems, paired with Zebron™ ZB-MultiResidue™ GC columns, to streamline EPA Method 508.1. Key goals include assessing recoveries, precision, accuracy, and operational efficiency.

Methodology and Instrumentation

• Sample Preparation: Automated SPE using SmartPrep Cartridge Extractor with Strata C18-E 1000 mg/6 mL cartridges and DryVap Concentrator with DryDisk membranes.
• Extraction Protocol: pH adjustment to ~2, addition of surrogate and spike solutions, sequential conditioning, sample loading, cartridge elution with organic solvents, nitrogen purging, and concentration to 1 mL.
• GC/ECD Analysis: Agilent HP 5890 Series II GC/ECD with Zebron ZB-MultiResidue-1 (30 m×0.32 mm×0.50 µm) and ZB-MultiResidue-2 (30 m×0.25 mm×0.25 µm) columns; helium carrier gas; oven program from 120 °C to 300 °C; detector at 320 °C.

Main Results and Discussion

• Calibration was linear from 0.1 to 2.0 µg/mL; DDT and Endrin degradation monitored.
• ZB-MultiResidue-2 resolved co-elutions (e.g., Simazine/Atrazine, d-BHC/Metribuzin) seen on ZB-MultiResidue-1.
• Average recoveries across 12 laboratory control samples were ~93% with RSD ≤17% for all reportable analytes.
• Method performance met EPA 508.1 precision and accuracy criteria.

Benefits and Practical Applications

• Automation increases throughput to 12 samples per run and reduces hands-on time.
• Strata C18-E cartridges provide strong hydrophobic retention with minimal secondary interactions.
• DryVap and DryDisk systems automate drying and concentration, cutting solvent use and manual steps.
• Zebron GC columns tailored for pesticides yield robust separations.

Future Trends and Potential Applications

Integration with advanced detection techniques such as LC–MS/MS, development of greener sorbent materials, further miniaturization and lab-on-a-chip approaches, and AI-driven method optimization represent emerging directions. These advances will support environmental monitoring, industrial QA/QC, and regulatory compliance workflows.

Conclusion

The workflow combining Strata C18-E SPE, Horizon automated extraction and concentration systems, and Zebron ZB-MultiResidue GC columns provides a high-throughput, accurate, and resource-efficient solution for EPA Method 508.1 analysis of chlorinated pesticides and organohalides in water.

References

• EPA Method 508.1: Chlorinated Pesticides, Herbicides, and Organohalides Analysis in Water.
• Horizon Technology, Inc. SmartPrep™ and DryVap® Systems; Phenomenex Strata® C18-E Cartridges; Zebron™ ZB-MultiResidue™ Columns.