Unparalleled performance of Advanced Electron Ionization GC-MS/MS technology for the determination of nitrosamines in drinking water

Significance of the Topic

Trace-level nitrosamines are potent carcinogens that can form in drinking water during disinfection processes. Monitoring these compounds at ultra-trace concentrations is critical for public health and regulatory compliance.

Study Objective and Overview

This study evaluated the quantitative performance of a Thermo Scientific TSQ 9000 triple quadrupole GC-MS/MS system equipped with an Advanced Electron Ionization (AEI) source for the analysis of seven priority nitrosamines in drinking water. Seventeen water samples from European treatment facilities were tested to assess sensitivity, linearity, limits of detection, quantitation, and real-world applicability.

Methodology and Sample Preparation

Samples were processed by solid-phase extraction using activated charcoal cartridges. One-liter water aliquots were spiked with deuterated standards (NDMA-d6, NDEA-d10) and concentrated 1,000-fold to 1 mL final extract. Calibration curves spanned 0.05–100 ng/L equivalent. Evaluation steps included assessment of instrument detection limits, method detection limits, limit of quantitation, carryover, linearity, precision, and recovery.

Used Instrumentation

• Thermo Scientific TRACE 1310 GC with splitless injection
• Thermo Scientific TSQ 9000 triple quadrupole MS with AEI source
• TraceGOLD TG-1701 MS capillary column (30 m × 0.25 mm, 0.5 µm)
• TriPlus RSH autosampler
• Chromeleon Chromatography Data System for data acquisition and processing

Main Results and Discussion

Chromatographic separation of seven nitrosamines was achieved in under nine minutes, improving throughput threefold over standard methods. The AEI source delivered on-column instrument detection limits down to 0.003 ng/L, and method detection limits ranged from 0.008 to 0.045 ng/L. Limits of quantitation were established between 0.1 and 0.5 ng/L, with ion ratio deviations and precision meeting rigorous criteria. Calibration curves exhibited R² values >0.999 and response factor RSDs <5%. Recovery of fortified water samples at 50 ng/L ranged from 80.7% to 111.1%. Analysis of 17 drinking water samples revealed total nitrosamine concentrations between 0.9 and 4.5 ng/L, all below regulatory thresholds.

Benefits and Practical Applications

High selectivity and sensitivity enable reliable detection of nitrosamines at sub-ppt levels.
Fast cycle times support high sample throughput and cost efficiency.
Robust quantitation and low carryover suit routine monitoring and QA/QC laboratories.
Compliance with global regulatory limits and emerging guidelines.

Future Trends and Potential Uses

Integration with automated on-line SPE for continuous monitoring.
Extension of the AEI GC-MS/MS platform to other semi-volatile organic contaminants.
Adoption in regulatory frameworks for potable water quality.
Coupling with data-driven workflows and AI for predictive water quality assessment.

Conclusion

The TSQ 9000 GC-MS/MS system with AEI source demonstrates unparalleled performance for ultra-trace nitrosamine analysis in drinking water, combining exceptional sensitivity, rapid chromatography, and robust quantitation. This platform is ideally positioned for routine regulatory compliance and industry-leading environmental monitoring.

References

• Mitch W. A., Sharp J. O. et al. N-nitrosodimethylamine (NDMA) as a drinking water contaminant: A review. Environmental Engineering Science, 2003, 20(5), 389–404.
• Sedlak D. L., Deeb R. A. et al. Sources and fate of nitrosamines and its precursors in municipal waste water treatment plants. Water Environmental Research, 2005, 77(1), 32–39.
• California Water Boards. NDMA and Other Nitrosamines – Drinking Water Issues. 2018.
• Ontario Ministry of the Environment and Energy. Regulation under the Ontario Water Resources Act: Drinking Water Protection Larger Water Works. 2003.
• Thermo Scientific Technical Note 51797. Timed SRM: Improved Capabilities for Multi-target Compound Analysis, 2009.