TRIAZINES WITH ON-LINE COUPLING SPE-GC

Importance of the Topic

Solid-phase extraction (SPE) is essential for cleaning and concentrating trace analytes prior to gas chromatographic analysis. Coupling SPE directly with GC streamlines workflows, improves sensitivity, and reduces sample handling errors.

Objectives and Study Overview

This application note describes the development of a fully automated online SPE–GC system for the analysis of triazine herbicides. The goal was to integrate a PROSPEKT SPE unit with an OPTIC2 large-volume injector and an HP6890 GC to achieve efficient sample enrichment and seamless analyte transfer.

Methodology and Instrumentation

The experimental setup combined:

• HP6890 gas chromatograph with flame ionization detector (FID)
• PROSPEKT SPE module (Spark Holland) with syringe-pump solvent delivery
• OPTIC2 large-volume injector serving as interface
• GC column: 15 m DB-1, 0.32 mm i.d., 0.25 µm film thickness

Method development steps:

1. GC condition optimization for triazine separation
2. OPTIC2 parameter tuning: maximum injection volume, solvent venting time, and temperature program
3. SPE optimization: cartridge conditioning, sample loading (3 mL/min for 5 min), washing, and helium drying (15 min)
4. Coupling adjustments: tubing internal volumes, eluent flow rates, and valve configurations

Main Results and Discussion

Online SPE–GC analysis of a standard mixture (8 ppb) produced well-resolved peaks within 10.25–13.27 min. Key findings:

• Retention times: desisopropyl atrazine (10.25 min), desethylatrazine (10.49 min), simazine (11.63 min), atrazine (11.86 min), propazine (12.08 min), terbuthylazine (12.34 min), sebuthylazine (13.27 min)
• Recoveries ranged from 85% (simazine) to 100% (desethylatrazine, propazine); desisopropyl atrazine data unavailable due to co-elution with an impurity

The OPTIC2 injector held the eluate at 45 °C to evaporate ethyl acetate and vent solvent, then ramped temperature to transfer analytes onto the GC column.

Benefits and Practical Applications

Automated online SPE–GC reduces manual steps, minimizes solvent use, and enhances repeatability and sensitivity. This approach is highly suitable for environmental monitoring of pesticide residues and routine trace analysis in QA/QC laboratories.

Future Trends and Opportunities

Emerging developments may include integrating mass spectrometric detectors for improved selectivity, utilizing micro- or nanocartridge SPE for rapid screening, adopting greener solvents, and implementing high-throughput automation for large sample batches.

Conclusion

The fully automated online SPE–GC system demonstrated robust enrichment and separation of triazine compounds with excellent recoveries, offering a streamlined solution for trace-level pesticide analysis.

References

van Egmond W.; Colen R.; Haak G.; Halmingh O. Application Note No. 013: Triazines with On-Line Coupling SPE-GC. ATAS B.V. and SPARK HOLLAND.