The Vision Automated Solid Phase Extraction System for GC-MS: An Evaluation of its Performance for Triazine Herbicides at ng/L Levels in Drinking Water

Significance of the Topic

The monitoring of triazine herbicides in drinking water at parts-per-trillion levels is mandated by regulatory bodies to ensure public health protection. Automated solid phase extraction (SPE) systems offer high reproducibility and efficiency, addressing the stringent requirements for low detection limits and precision in environmental analysis.

Study Objectives and Overview

This study evaluates the Vision Automated Solid Phase Extraction System coupled to GC-MS in SIM mode for the trace analysis of triazine herbicides in tap water. Key goals include verifying compliance with UK regulations (reporting level 100 ng/L, detection limit 20 ng/L) and assessing precision (%RSD ≤ 5%) for replicate extractions.

Methodology and Instrumentation

The procedure involved automated conditioning, sample loading, drying, and elution steps within the Vision platform. A 7.5 mL aliquot of spiked water (20–100 ng/L) passed through a styrene-divinyl benzene SPE cartridge. Elution was performed with ethyl acetate and directly injected (50 µL) into GC-MS.

Used instrumention:

• Vision SPE system with Midas autosampler, Prospekt solvent unit, HPLC pump
• Optic 2-200 programmable injector
• Shimadzu GC-17A chromatograph with QP-5000 MS in SIM mode
• CP-Sil 5CB-MS capillary column (50 m × 0.25 mm × 0.4 µm)
• SPE cartridges (10 mm × 2 mm, 15–25 µm styrene-divinyl benzene)

Main Results and Discussion

The system achieved precision between 1.32% and 4.82% RSD at the 100 ng/L level for most triazines, with two exceptions: des-isopropyl atrazine (7.23% RSD) and ethyl parathion (15.33% RSD) due to co-eluting interference. Detection limits derived from 20 ng/L spikes ranged from 0.73 to 9.26 ng/L, comfortably below the 20 ng/L target for all analytes.

Benefits and Practical Applications

The automated SPE approach streamlines sample preparation, minimizes manual handling errors, and delivers reproducible extraction efficiency. Laboratories performing routine water quality monitoring can achieve regulatory compliance and high throughput with reduced operator time.

Future Trends and Applications

Advances in SPE automation may include integration with multi-residue workflows, adoption of greener solvents, and real-time data feedback for process optimization. Coupling with high-resolution mass spectrometry could further enhance selectivity and lower detection thresholds for emerging contaminants.

Conclusion

The Vision Automated SPE system demonstrates reliable performance for trace-level determination of triazine herbicides in drinking water. It meets regulatory requirements for detection limits and precision while offering operational advantages for environmental laboratories.