A portable fast gas chromatography-mass spectrometry workflow for quantification of biogenic volatile organic compounds with humidity‑dependent sensitivity correction.

Biogenic volatile organic compounds (BVOCs) regulate key atmospheric and ecological processes but remain challenging to quantify in the field due to reactivity, mixture complexity, and variable ambient humidity. A portable fast Gas Chromatography-Mass Spectrometry (GC-MS) workflow was developed, coupling needle-trap (NT) sampling with a compact GC-MS system to enable BVOC quantification with minimal logistics. A 15-compound gas standard (28-91 µmol mol⁻¹) was generated under controlled water vapor pressures (ea = 0.7-2.3 kPa), and two independent calibrations sessions were performed to assess reproducibility. Seven compounds (α-pinene, benzene, chlorobenzene, 1,2-dichlorobenzene, isoprene, toluene, and o-xylene) exhibited linear responses (R² > 0.85) across humidity levels. Calibration sensitivity showed a strong exponential dependence on ea , and compound-specific correction functions were derived. Concentrations estimated from portable GC-MS showed excellent agreement with Proton Transfer Reaction Mass Spectrometry (PTR-MS) reference values (R² > 0.94). Six additional VOCs were detected but not reliably quantified under 3- min GC conditions. The method provides a 15- min sampling-to-result cycle and requires only 40 mL of air. The working limit of quantification was approximately 40 ppb, making the method primarily suited to chamber or enriched‑air applications where BVOC levels exceed this threshold.•Portable NT + fast GC-MS workflow for in-field BVOC quantification.•Humidity-dependent exponential sensitivity functions used for correction.•Good agreement with PTR-MS reference concentrations (R² > 0.94).