Staying Ahead in a Rapidly Changing World - Application Compendium

Significance of the Topic

• The global helium shortage and rising costs have driven analytical laboratories to seek hydrogen (H2) as an alternative GC carrier gas.
• Hydrogen offers faster separations and improved efficiency but can induce hydrogenation or dechlorination reactions in conventional EI sources, compromising spectral fidelity and quantitative accuracy.
• The development of the Agilent HydroInert extractor source and optimized GC conditions enables reliable GC/MS and GC/MS/MS analyses of semivolatile and volatile organic compounds (SVOCs and VOCs) in environmental and drinking water matrices using H2 carrier gas.

Objectives and Overview

• Demonstrate the performance of the Agilent HydroInert source on single-quadrupole (5977B/C), triple-quadrupole (7000 series), and headspace GC/MS systems when using H2 carrier gas.
• Establish methods for EPA Method 8270 analyses of semivolatiles across 0.1–100 µg/mL on single-quad and 0.02–100 µg/mL on triple-quad platforms.
• Develop a rapid headspace GC/MS method for 80 VOCs in drinking water over 0.05–25 µg/L in under 8 minutes.

Used Instrumentation

• Agilent 8890 GC with multimode inlet (split/splitless and pulsed split capability).
• Agilent 5977B/C Inert Plus single-quad MSD and 7000 series triple-quad GC/MS/MS with HydroInert extractor source (9 mm lens).
• Agilent J&W DB-5ms or DB-624 UI columns (20 m × 0.18 mm, 0.18–0.36 µm) tailored for H2 carrier flow (1.2 mL/min).
• Agilent 8697 Headspace Sampler configured for static headspace of water samples with salt addition and loop volume optimization.
• Agilent MassHunter software for data acquisition, spectral deconvolution (Unknowns Analysis), and quantitative processing in scan and SIM/dMRM modes.

Methodology and Experimental Conditions

• SVOC single-quad and triple-quad: Stock mixes of 119–120 analytes and surrogates were prepared and diluted in dichloromethane. Pulsed split injection (10–20:1), inlet temperature ramps (230–350 °C), and GC temperature programs (30 °C/min ramps to 320 °C) were optimized for 12 min runs.
• VOCs headspace: 80 compounds in water vials spiked with salts and ISTDs, equilibrated at 75 °C for 12 min, loop sampled (1 mL), and analyzed via a pulsed split 21:1 injection into a DB-624 UI column with H2 carrier gas.
• Data acquisition in full-scan mode (35–500 m/z or 35–260 m/z) and SIM/dynamic MRM for enhanced sensitivity. Etune was used for autotuning; DFTPP or PFTBA tune criteria were met per EPA 8270D/E requirements.

Main Results and Discussion

• Mass spectral fidelity: Nitrobenzene exhibited negligible hydrogenation to aniline when using the HydroInert source with H2, maintaining correct MRM and scan spectra (123/93 m/z ratios) compared to an extractor source.
• Tune criteria: DFTPP ion ratio checks passed all EPA 8270D/E requirements with minimal DDT breakdown (<1.4 %) and tailing factors <1.5 for pentachlorophenol and benzidine.
• Critical isomer resolution: Phenanthrene/anthracene, benz[a]anthracene/chrysene, and benzo(b)fluoranthene/benzo(k)fluoranthene achieved >50 % resolution in 12 min runs.
• Calibration performance: Over 87 % of SVOCs on single-quad and 92.5 % of VOCs achieved default calibration ranges; 77 SVOCs on triple-quad reached extended 0.02–100 µg/mL. Average RF %RSDs were <20 %, with only a small number of compounds requiring linear or quadratic fits.
• Matrix repeatability: 10-injection soil matrix spiked at 15 µg/mL SVOC standard yielded <7 % RSD for all compounds and recoveries within ±20 %. Headspace water matrix analysis at 0.4 µg/L VOC spike gave >85 % of compounds within ±20 % calibration verification limits, with <12 % RSD.

Benefits and Practical Applications

• Enables laboratories to replace helium with hydrogen without redevelopment of established EPA-compliant methods.
• Reduces operating costs and reliance on scarce helium supplies while maintaining sensitivity, accuracy, and spectral integrity.
• Shortens analysis time through efficient pulsed split injections and optimized temperature programs, increasing sample throughput.
• Supports wide-ranging environmental, industrial, and QA/QC workflows for soil, water, and food matrices.

Future Trends and Potential Applications

• Integration of H2-based methods in comprehensive two-dimensional GC/MS (GC×GC) for enhanced separation of complex mixtures.
• Application to trace-level pesticide, endocrine disruptor, and emerging contaminant analyses in various matrices.
• Automation of source optimization and real-time spectral fidelity monitoring to further streamline method transfer to H2 carrier gas.
• Exploration of alternative carrier gases (e.g., nitrogen or formic acid–stabilized H2) to further improve green analytical chemistry footprints.

Conclusion

The Agilent HydroInert source coupled with optimized GC parameters and hydrogen carrier gas provides robust, high-fidelity GC/MS and GC/MS/MS analyses of SVOCs and VOCs. The methods meet EPA 8270D/E criteria, retain existing spectral libraries and MRM transitions, and deliver fast separations with consistent quantitation in environmental and drinking water samples. This technology offers laboratories a cost-effective, sustainable alternative to helium, with minimal method redevelopment and maintained analytical confidence.

References

1. United States Environmental Protection Agency. Method 8270D: Semivolatile Organic Compounds by Gas Chromatography/Mass Spectrometry; Revision 4, February 2007.
2. United States Environmental Protection Agency. Method 8270E: Semivolatile Organic Compounds by Gas Chromatography/Mass Spectrometry; Revision 4, June 2018.
3. Smith Henry, A. Analysis of Semivolatile Organic Compounds with Agilent Sintered Frit Liner by GC/MS, Agilent Technologies, Application Note 5994-0953EN, 2019.
4. Churley, M.; Quimby, B.; Andrianova, A. A Fast Method for EPA 8270E with Pulsed Split Injection on 8890/5977, Agilent Technologies, Application Note 5994-1500EN, 2020.
5. Quimby, B. D.; Andrianova, A. A. Volatile Organic Compounds in Drinking Water by HS-GC/MS with H2 Carrier and HydroInert Source, Agilent Technologies, Application Note 5994-4890EN, 2022.