Determination of BTEX and volatile organic compounds (VOCs) in drinking water by GC-MS/MS coupled to static headspace and solid-phase microextraction sampling

Significance of the Topic

Volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene, and xylenes (BTEX), together with halogenated hydrocarbons, represent widespread environmental contaminants. Their high volatility and toxicity pose health risks when present in drinking water. Regulatory bodies worldwide set strict maximum contaminant levels (0.1–0.3 µg/L) to protect public health and ensure water quality.

Objectives and Study Overview

This application note evaluates two sampling approaches—static headspace (SHS) and solid-phase microextraction Arrow (SPME Arrow)—coupled to a Thermo Scientific TSQ 9000 triple quadrupole GC-MS/MS system. The goal is to compare sensitivity, linearity, detection limits, recovery, and automation capabilities for quantifying BTEX and chlorinated/brominated VOCs in drinking water.

Methodology and Instrumentation

Automated extraction was performed on a Thermo Scientific TriPlus RSH autosampler configured for SHS and HS-SPME Arrow modes. A Carbon Wide Range/PDMS SPME Arrow fiber enabled trace-level enrichment. Separation used a TraceGOLD TG-624SilMS capillary column with hydrogen as carrier gas for fast chromatography. Detection employed a TSQ 9000 GC-MS/MS with an ExtractaBrite ion source, operating in timed-SIM for rapid screening and SRM for high-selectivity analyses. Data handling was integrated in Chromeleon CDS software for full automation and regulatory compliance.

Main Results and Discussion

The methods achieved baseline separation of 26 analytes with excellent chromatography and low bleed. Calibration was linear over regulatory ranges (R² > 0.990; average calibration factor %RSD < 9%). Method detection limits (MDLs) ranged from 0.01 to 0.13 µg/L; SPME Arrow was essential to meet the lowest MDLs (0.01–0.05 µg/L) for compounds like vinyl chloride. Recoveries across all analytes were 60–130%. Over a 48-hour, 129-sample sequence, retention times remained stable (RSD < 0.04 min), peak area RSD < 11%, and carryover was below 0.01%.

Benefits and Practical Applications

• Automated SHS and SPME Arrow sampling reduces manual preparation and solvent use.
• Detects VOCs and BTEX at or below regulatory limits (0.1–0.3 µg/L).
• High sample throughput enabled by fast GC oven ramps and autosampler overlap.
• Flexible acquisition in SIM for screening or SRM for interference-free quantification.

Future Trends and Possibilities

Developments in fiber coatings and autosampler SMART features will enhance sensitivity and expand compound coverage. Next-generation GC-MS/MS instruments with broader dynamic range will facilitate trace-level monitoring of emerging contaminants. Advances in real-time and on-site VOC detection may drive new regulatory and field-deployable solutions.

Conclusion

The combination of SHS and SPME Arrow sampling with the TSQ 9000 GC-MS/MS system offers a robust, sensitive, and fully automated workflow for comprehensive VOC and BTEX analysis in drinking water. It ensures compliance with stringent regulatory requirements while maximizing laboratory efficiency.

References

• U.S. Environmental Protection Agency. Technical Overview of Volatile Organic Compounds.
• U.S. Environmental Protection Agency. Safe Drinking Water Act (SDWA).
• Council of the European Union. Directive 2008/105/EC on environmental quality standards in the field of water policy.
• Extension Foundation. Drinking Water Contaminant—Volatile Organic Compounds (VOCs).
• ISO 11423-1:1997. Water quality—Determination of benzene and some derivatives—Head-space gas chromatographic method.
• ISO 10301:1997. Water quality—Determination of highly volatile halogenated hydrocarbons—Gas-chromatographic methods.
• Pawliszyn J., et al. Theory of Solid-Phase Microextraction, Journal of Chromatographic Science, 2000, 38, 270–278.
• ASTM D6520-00. Standard Practice for the Solid Phase Micro Extraction (SPME) of Water and its Headspace.
• ASTM D6889-03. Standard Practice for Fast Screening for Volatile Organic Compounds in Water Using SPME.
• ISO 17943:2016. Water quality—Determination of volatile organic compounds in water—HS-SPME GC-MS method.
• Tuduri L., Desauziers V., Fanlo J.L. Potential of Solid-Phase Microextraction Fibers for the Analysis of VOCs in Air, Journal of Chromatographic Science, 2001, 39, 521–529.
• Thermo Fisher Scientific. TSQ 9610 Triple Quadrupole GC-MS/MS System Brochure.
• Thermo Fisher Scientific. TriPlus RSH SMART Robotic Sampling System Brochure.