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

Significance of the Topic

Halogenated disinfection byproducts and chlorinated solvents in drinking water are subject to stringent regulatory limits due to their potential adverse health effects. Reliable detection at ultra-trace levels is essential for ensuring water safety and compliance with evolving standards.

Study Objectives and Overview

This study evaluated the performance of a Thermo Scientific TRACE 1310 Gas Chromatograph equipped with dual columns and dual electron capture detectors for the simultaneous quantification and confirmation of 17 halogenated disinfection byproducts and chlorinated solvents in drinking water.

Methodology and Instrumentation

Sample Preparation

• Buffered deionized water (pH 4.8–5.5) with ammonium chloride to prevent further byproduct formation
• Spiking with mixed primary standards and decafluorobiphenyl surrogate
• Liquid-liquid extraction using methyl tert-butyl ether (MTBE) and sodium sulfate
• Phase separation and direct analysis of the organic extract

Instrumentation

• Thermo Scientific AI/AS 1310 autosampler with single-inlet splitless injection
• 3-Port microfluidic splitter delivering a 1:1 flow split to two TraceGOLD columns (TG-1MS primary, TG-1301MS confirmatory)
• Dual Instant Connect electron capture detectors operated at 290 °C, pulse amplitude 50 V
• Chromeleon CDS software for automated control, data processing, and reporting

Key Results and Discussion

Chromatographic Performance

• High resolution (Rs > 1.0) achieved for critical pairs (e.g., bromodichloromethane vs. trichloroethene)
• Peak Gaussian factors between 0.8 and 1.15, indicating excellent peak shape

Linearity and Sensitivity

• Calibration ranges yielded R2 ≥ 0.995 and average calibration factor %RSD < 11 for all analytes
• Instrument detection limits (IDL) in the femtogram on-column range
• Method detection limits (MDL) below 0.03 µg/L, meeting or exceeding EPA Method 551.1 requirements

Recovery and Precision

• Spiked drinking water samples at mid-range levels showed recoveries of 80–120%
• Precision (%RSD) of concentration measurements below 10% for all analytes

Benefits and Practical Applications

The dual-column, dual-ECD configuration provides robust confirmation alongside quantification, high throughput, and cost-effective operation. The fully automated workflow supports routine QA/QC and regulatory compliance testing in environmental and drinking water laboratories.

Future Trends and Opportunities

Advances may include integration with mass spectrometry for broader analyte coverage, online sample preparation techniques to reduce manual handling, further miniaturization of microfluidic components, and implementation of AI-driven data analysis. Tightening regulatory limits will continue to drive the demand for even lower detection limits and real-time monitoring solutions.

Conclusion

The TRACE 1310 GC with dual ECD detectors and dual columns delivers sensitive, precise, and confirmatory analysis of halogenated disinfection byproducts and chlorinated solvents in drinking water. The method meets stringent regulatory requirements and is readily adoptable for routine laboratory use.

References

1. United States Environmental Protection Agency. National Primary Drinking Water Regulations. Accessed January 2020.
2. United Kingdom Drinking Water Inspectorate. Water Quality Standards. Accessed January 2020.
3. United Kingdom Drinking Water Inspectorate. Micro and Chemical Risks in Private Water Supplies. Accessed January 2020.
4. Centers for Disease Control and Prevention. Chlorination Disinfection Byproducts in Drinking Water. Accessed January 2020.
5. Munch DJ and Hautman DP. EPA Method 551.1: Determination of Chlorination Disinfection Byproducts, Chlorinated Solvents and Halogenated Pesticides/Herbicides in Drinking Water by Liquid-Liquid Extraction and GC-ECD, Revision 1.0.