Automated sample preparation followed by sensitive analysis by GC-MS/MS for environmental contaminants in surface waters

Importance of Topic

Environmental pollutants in surface waters pose ongoing risks to ecosystems and human health. Reliable, high-throughput methods are essential to monitor trace levels of semi-volatile organic contaminants while minimizing reagent use, labor costs, and exposure risks. Automating sample preparation coupled with sensitive GC-MS/MS analysis addresses these challenges, enabling laboratories to increase productivity and maintain rigorous quality standards.

Goals and Study Overview

This work evaluates a fully automated liquid–liquid extraction workflow for semi-volatile contaminants in surface water using the Thermo Scientific Triplus RSH autosampler and TRACE 1310 GC coupled to TSQ 9000 triple quadrupole MS/MS with an Advanced Electron Ionization (AEI) source. Objectives include demonstrating:

• Feasibility of end-to-end automated extraction and injection
• Ultra-low detection limits across a multi-class analyte panel
• Linearity, repeatability, and compliance with regulatory standards

Methodology and Instrumentation

Automated sample preparation uses a headspace vial-based liquid-liquid extraction with pentane as the solvent. Key steps:

1. Transfer 10 mL of surface water to a 20 mL vial
2. Add isotopically labeled internal standards
3. Introduce 2 mL pentane, vortex 1 min at 2000 cycles/min
4. Allow 5 min phase separation
5. Perform a large-volume PTV injection (50 µL) into GC

The GC-MS/MS system comprises:

• TRACE 1310 GC with Instant Connect PTV injector
• TraceGOLD TG-5-SilMS capillary column (60 m × 0.25 mm × 0.25 µm)
• Triplus RSH autosampler (vortex mixer, multi-syringe manifold)
• TSQ 9000 triple quadrupole MS/MS with AEI source
• Data acquisition and processing via TraceFinder software with SRM libraries

Main Results and Discussion

Calibration and linearity were assessed over eight concentration levels from 5 to 1000 ng/L. All 60 target compounds exhibited:

• Correlation coefficients ≥ 0.995
• Residuals within ± 25%

Repeatability was evaluated by ten replicate analyses of surface water spiked at 100 ng/L, yielding relative standard deviations below 6% for most analytes. Instrument detection limits ranged from 0.22 to 17.8 ng/L, demonstrating robust sensitivity at ultra-trace levels. The automated workflow reduced hands-on time, minimized solvent consumption (2 mL per sample), and maintained compliance with ISO/IEC 17025 and EU performance criteria.

Benefits and Practical Applications

Implementation of the automated system delivers:

• Significant labor savings and reduced analyst exposure
• Lower solvent costs and environmental footprint
• High-throughput capacity with consistent precision
• Regulatory compliance for multi-class pollutant monitoring

Such an approach is valuable for water quality laboratories, environmental monitoring agencies, and industrial QA/QC facilities.

Future Trends and Opportunities

Emerging developments may include:

• Integration of additional extraction modes (e.g., solid-phase microextraction)
• Advanced data mining and AI-driven compound identification
• Expanded analyte coverage including new pollutants of concern
• Miniaturized and green extraction techniques
• Remote and field-deployable automated systems for on-site monitoring

Conclusion

The combined Triplus RSH–TSQ 9000 AEI GC-MS/MS configuration offers a turnkey solution for automated, sensitive, and reproducible analysis of environmental contaminants in surface waters. By streamlining sample handling and ensuring high analytical performance, laboratories can achieve reliable results while optimizing resource use.

Reference

• Kalachova et al. Analysis of emerging persistent organic pollutants using GC-MS/MS; SETAC, Berlin 2012.
• Ziegenhals, K.; Hubschmann, H.J. Fast-GC/HRMS to quantify the EU priority PAH. J. Sep. Sci. 2008, 31, 1779–1786.
• Cole J. Thermo Scientific Application Brief AB52998 - Introducing AutoSRM: MRM Simplicity for High Performance Results.
• REGULATION (EC) No 2002/657 on analytical performance criteria.
• Pesticides Method Reference, 2nd ed. 2011, Thermo Fisher Scientific, Austin, TX, USA, P/N 120390.
• SampleQ. www.sampleQ.nl.
• Het Waterlaboratorium. www.hetwaterlaboratorium.nl.