Agilent Inert Plus GC/MS System with HydroInert Source

Importance of the topic

Gas chromatography–mass spectrometry remains a cornerstone of analytical chemistry across environmental monitoring, food safety, forensic toxicology and industrial quality control. Recent pressure on the global helium supply has driven demand for alternative carrier gases. Hydrogen offers rapid separations and on-site generation but can induce hydrogenation and dechlorination reactions in conventional EI sources. The Agilent HydroInert source addresses these challenges and unlocks the benefits of hydrogen carrier gas without compromising mass spectral fidelity.

Objectives and study overview

This study evaluates the performance of the HydroInert EI source installed in Agilent Inert Plus GC/MS and GC/MS/MS platforms when using hydrogen carrier gas. Key goals include maintaining existing helium-based library compatibility, preserving compound identification across diverse analyte classes, measuring sensitivity and linear range, and assessing source maintenance requirements.

Methodology and used instrumentation

Experiments were conducted on Agilent 5977B Inert Plus single quadrupole and 7000D/E triple quadrupole GC/MS systems equipped with HydroInert sources and 9 mm extraction lenses. An Agilent 8890 GC and headspace samplers (7697A or 8697) were used for VOC, SVOC and pesticide analyses. Stainless steel tubing, gas filters and universal traps ensured gas purity. Test mixtures included nitroarenes, chlorinated pesticides (DDT, heptachlor), PAHs, hydrocarbon ladders, EPA 8270 SVOCs and trihalomethanes in water. Data were acquired in scan, SIM or MRM modes, with library match scores referenced against NIST17.L.

Key results and discussion

Use of hydrogen with a conventional extractor source caused extensive hydrogenation of nitrobenzene to aniline and dechlorination of DDT to DDD, leading to low library match scores. The HydroInert source largely eliminated these reactions, restoring expected spectra and high match scores within 2–5 % of helium benchmarks. In heptachlor analyses the correct chloride isotopic pattern was retained. Hydrocarbon ladders from C10 to C38 showed reduced peak tailing (factors 0.6–0.9 versus up to 10). EPA 8270D/E ion ratio and response factor criteria were met in GC/MS and GC/MS/MS modes. Headspace quantification of trihalomethanes at low µg/L levels achieved match scores above 80. Sensitivity and linearity for nitrobenzene (0.1–100 ng/µL) were comparable to helium, with RF RSD < 7 %. Extended source lifetime was observed with over 5 000 matrix injections before requiring maintenance versus ~ 365 for a standard source.

Benefits and practical applications

• Full compatibility with existing helium mass spectral libraries enables rapid transition to hydrogen without rebuilding databases.
• Faster chromatography and higher flow rates reduce analysis times and increase sample throughput.
• Reduced electron ionization source downtime and cleaning frequency improve laboratory productivity.
• Maintained sensitivity and linearity across regulated methods (EPA 8270, pesticide MRM, VOC headspace).
• Sustainable carrier gas solution with lower cost and on-demand generation.

Future trends and possibilities

Adoption of hydrogen carrier gas is expected to grow across routine and research laboratories. Further method validation for additional compound classes, integration with two-dimensional GC and automated gas switching hardware are promising developments. Expansion of hydrogen-compatible inert source designs could enable broader use in high-throughput and untargeted screening workflows.

Conclusion

The Agilent HydroInert source successfully mitigates hydrogen-induced reactions in GC/MS and GC/MS/MS, preserving mass spectral integrity and sensitivity. Laboratories can leverage hydrogen carrier gas to enhance throughput, reduce costs and conserve helium resources without sacrificing data quality or existing library assets.

Reference

1. Agilent Technologies. EI GC/MS Instrument Helium to Hydrogen Carrier Gas Conversion User Guide, publication 5994-2312EN, 2020.
2. Quimby B et al. In-Situ Conditioning in Mass Spectrometer Systems, US Patent 8,378,293, 2013.
3. US EPA. Method 8270D Semivolatile Organic Compounds by GC/MS, Revision 4, 2007.
4. US EPA. Method 8270E Semivolatile Organic Compounds by GC/MS, Revision 4, 2018.
5. Churley M, Quimby B, Andrianova A. Fast EPA 8270 Method in MRM Mode Using Triple Quadrupole GC/MS, application note 5994-0691EN, 2019.
6. Smith H. Analysis of SVOCs with Sintered Frit Liner by GC/MS, application note 5994-0953EN, 2019.
7. Andrianova A, Quimby B. Optimized PAH Analysis Using Triple Quadrupole GC/MS with Hydrogen Carrier, application note 5994-2192EN, 2020.