Analysis of Haloacetic Acids and Dalapon in Water by GC-MS Using TraceGOLD TG-5MS with SafeGuard GC Column

Significance of the Topic

Monitoring haloacetic acids and dalapon in drinking water is critical for public health and compliance with regulatory standards. These compounds arise as disinfection by products and herbicide residues that pose potential risks to human health at trace levels. Sensitive and reliable detection methods support water quality assurance and environmental protection.

Objectives and Study Overview

The study evaluates an ultra low bleed GC column with integrated guard column for confirmatory analysis of haloacetic acids and dalapon in water according to environmental protection agency method 552.2. The main goals are to assess sensitivity accuracy precision and column robustness when using GC MS in selected ion monitoring mode at concentration levels down to 250 nanograms per milliliter.

Methodology and Instrumentation

The analytical workflow involves liquid liquid extraction with methyl tert butyl ether followed by acid catalyzed derivatization in methanol. Sample prep includes pH adjustment salting out with sodium sulfate extraction and derivatization at controlled temperature under stirring. GC analysis is performed on a GC Ultra system coupled to a single quadrupole mass spectrometer operating under electron ionization and SIM focusing on ion 59. Key parameters include helium carrier gas split injection and a temperature program optimized for strong acid derivatives.

Used Instrumentation

• TraceGOLD TG 5SilMS column 30 m x 0.25 mm x 0.25 µm with 10 m SafeGuard guard section
• Thermo Scientific TRACE GC Ultra
• Thermo Scientific ISQ GC single quadrupole mass spectrometer
• Thermo Scientific TriPlus autosampler

Main Results and Discussion

The method achieved baseline separation of ten analytes including monochloroacetic acid monobromoacetic acid dichloroacetic acid dalapon and others within eighteen minutes. The ultra inert stationary phase minimized peak tailing for strongly acidic derivatives while the integrated guard provided peak refocusing and extended column life. Relative standard deviations across triplicate analyses at 250 ng/mL ranged from eight to eighteen percent demonstrating acceptable precision for confirmatory analysis.

Benefits and Practical Applications

• Improved peak shapes for acidic derivatives thanks to phenyl modified low bleed phase
• Extended column lifetime by protection against harsh derivatization reagents
• Compatibility with mass spectrometric detection enabling flexible quantitation and identification
• Compliance with regulatory method 552.2 for routine water quality monitoring

Future Trends and Opportunities

Advances may include coupling with detectors such as electron capture for dual detection strategies integration of inline sample preparation modules and adoption of greener solvents for extraction. Further miniaturization and high throughput formats could enhance routine surveillance of drinking water and environmental samples.

Conclusion

The TraceGOLD TG 5SilMS column with SafeGuard guard delivers robust reproducible and sensitive analysis of haloacetic acids and dalapon in water. Its low bleed inert phase and integrated protection meet the requirements for confirmatory identification under environmental protection agency method 552.2 and offer a practical solution for water quality laboratories.

Reference

1. EPA method 552.2 Determination of haloacetic acids and dalapon in drinking water by liquid liquid extraction derivatization and gas chromatography with electron capture detection