Analysis of halogenated disinfection byproducts and chlorinated solvents in drinking water by GC-dual ECD

Importance of the Topic

The monitoring of halogenated disinfection byproducts and chlorinated solvents in drinking water is critical to public health and regulatory compliance. These compounds, formed during water treatment or introduced through industrial contamination, pose carcinogenic and toxic risks at elevated concentrations. Highly sensitive and robust analytical methods are required to ensure water safety and adhere to stringent regulatory limits worldwide.

Study Objectives and Overview

This application note evaluates the performance of a Thermo Scientific TRACE 1310 Gas Chromatograph (GC) configured with dual columns and dual electron capture detectors (ECDs) for the quantification of 17 halogenated byproducts and chlorinated solvents in drinking water. Performance metrics include chromatographic resolution, sensitivity (instrument and method detection limits), linearity, and recovery in real water samples.

Methodology and Instrumentation

A liquid–liquid extraction using methyl tert-butyl ether (MTBE) and salt was employed to isolate analytes from buffered, dechlorinated water samples spiked with internal standards. The GC system comprised:

• TRACE 1310 GC with split/splitless injector
• Dual TraceGOLD columns: TG-1MS (primary) and TG-1301MS (confirmatory)
• Dual Instant Connect ECDs with microfluidic 3-port splitter (1:1 column flow)
• AI/AS 1310 autosampler
• Chromeleon CDS software for automation, data acquisition, and reporting

Calibration standards covered wide concentration ranges, and surrogate standard decafluorobiphenyl was used for recovery assessment.

Results and Discussion

Chromatographic resolution between critical peak pairs exceeded Rs 1.1 on the primary column, with Gaussian peak shapes (PGF 0.8–1.15). Linearity across the calibration range yielded R2 ≥ 0.995 and average calibration factor RSD < 11% for all analytes. Instrument detection limits (IDLs) were in the femtogram-on-column range, and method detection limits (MDLs) met or exceeded regulatory requirements (EPA Method 551.1). In seven replicate spiked water samples at mid-level concentration, recoveries ranged from 80% to 120%, with concentration RSD < 10%.

Benefits and Practical Applications

The dual-column dual-ECD configuration provides simultaneous quantification and confirmation in a single run, enhancing confidence in compound identification. The low-bleed TraceGOLD columns and high sensitivity ECDs enable ultra-trace detection without the complexity and cost of mass spectrometry. Full automation through Chromeleon CDS streamlines workflows and ensures data integrity for routine environmental and regulatory laboratories.

Future Trends and Potential Applications

Future developments may include integration of mass spectrometric confirmation, further lowering detection limits, and coupling online extraction techniques for higher throughput. Advances in column chemistries and microfluidic devices will continue to simplify dual-column setups and expand applicability to emerging contaminants.

Conclusion

The Thermo Scientific TRACE 1310 GC with dual ECD detection demonstrates a sensitive, accurate, and robust method for analyzing halogenated disinfection byproducts and chlorinated solvents in drinking water. It meets regulatory performance criteria and offers streamlined, automated workflows suitable for routine laboratory use.

References

• 1. United States Environmental Protection Agency. National Primary Drinking Water Regulations; accessed January 6, 2020.
• 2. United Kingdom Drinking Water Inspectorate. Drinking Water Standards; accessed January 6, 2020.
• 3. United Kingdom Drinking Water Inspectorate. Private Water Supply Installations: Micro- and Chemical Requirements; accessed January 6, 2020.
• 4. Centers for Disease Control and Prevention. Chlorination Disinfection Byproducts; accessed January 6, 2020.
• 5. U.S. EPA Method 551.1. Determination of Chlorination Disinfection Byproducts, Chlorinated Solvents and Halogenated Pesticides/Herbicides in Drinking Water by Liquid–Liquid Extraction and Gas Chromatography with Electron Capture Detection, Revision 1.0.