Automated liquid-liquid extraction (LLE) for on-line GC-MS/MS and GC-FID analyses of drinking and waste waters

Significance of the Topic

Automated extraction methods are critical to meet the growing demand for high-throughput and reliable monitoring of semi-volatile organic compounds in drinking and wastewater.
Integration of robotic liquid-liquid extraction reduces manual bottlenecks, limits solvent consumption and exposure risks, and ensures compliance with stringent environmental regulations.

Objectives and Study Overview

VERITAS Integrated Water Service Laboratory sought to address a doubling in monthly sample volume by automating the LLE workflow prior to GC-MS/MS and GC-FID analyses.
The case study focuses on the implementation of the TriPlus RSH autosampler combined with TSQ 9000 GC-MS/MS and GC-FID instrumentation to enhance sensitivity, throughput and resource efficiency.

Methodology and Instrumentation

The automated workflow replaces manual separatory funnel steps with in-vial LLE, internal standard addition and vortex mixing under autosampler control.
Extraction and analysis steps are overlapped to operate continuously, extending throughput to nights and weekends.
Syringe selection is automated to carry out solvent addition, IS spiking and GC injection with minimal cross-contamination.

Instrumentation Used

• Thermo Scientific TriPlus RSH Robotic Sample Handling autosampler
• Thermo Scientific TRACE 1300 Series GC with iConnect Programmable Temperature Vaporizing Injector
• Thermo Scientific TSQ 9000 triple quadrupole GC-MS/MS with Advanced Electron Ionization Source
• GC-FID system for mineral oil (Hydrocarbon Index) analysis
• Thermo Scientific Chromeleon Chromatography Data System with intelligent sequencing

Main Results and Discussion

Sample throughput increased from 22 000 per year in 2016 to a projected 50 000 in 2022, with turnaround times reduced from ten to three days.
Automated LLE lowered solvent use by more than 500-fold, switching from 200 mL dichloromethane to 2 mL n-pentane per sample and reducing total consumption from 500 L/year to ~12 L/year.
Sample volume requirements fell from 1 L to 10 mL, cutting storage and transport costs.
Large-volume injection (40–50 µL) and the AEI source maintained ultra-sensitive detection (e.g., benzo(a)pyrene at 0.0025 µg/L) despite smaller extract volumes.
Chromeleon CDS integration with LIMS and conditional workflows optimized cleanup steps and reagent use.

Benefits and Practical Applications

• Significant reduction of manual labor and associated errors
• Enhanced reproducibility through precise robotic handling
• Lower operational costs via reduced solvent, sample volume and waste
• Improved laboratory safety by minimizing exposure to hazardous chemicals
• Continuous operation allows overnight and weekend processing
• Flexibility to adapt methods, solvents and sample racks per workload

Future Trends and Applications

Emerging demands for greener solvents and further miniaturization will drive advanced automation in environmental analysis.
Integration of artificial intelligence and real-time data analytics can enable predictive maintenance and adaptive method optimization.
Expanding the automated workflow to other matrices (soil, food, biological fluids) and coupling with high-resolution MS may broaden contaminant coverage.

Conclusion

The implementation of TriPlus RSH automation with high-sensitivity GC-MS/MS and GC-FID platforms successfully transformed VERITAS laboratory operations.
Automated in-vial LLE addressed capacity challenges, improved compliance with regulatory limits, and delivered cost savings and safety gains.
This case exemplifies how robotics integration can modernize environmental analytical laboratories.

References

No additional references were provided in the source document.