Selection, optimization, and validation of thermal desorption for analysis of VOCs and PAHs in combustion emissions

The simultaneous analysis of volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) in smoke requires robust and efficient sampling methods due to complex matrix effects. This study evaluated and optimized multibed thermal desorption tubes for the capture and analysis of VOCs and PAHs. Sorbent bed type was first assessed, revealing concentration-dependent differences in analyte retention, with Tenax TA and Carbopack X providing consistently the highest peak areas at 10 μg/mL. A factorial design study examined desorption parameters (temperature, time, and flow), showing minimal effect on peak area, indicating method robustness. Storage trials over 35 days highlighted the need for quality control when samples are stored. Conditioning optimization demonstrated that reduced times (1 h) and temperatures (250 °C) efficiently removed analytes up to C16, minimizing thermal artifacts. Overall, the combination of Tenax TA and Carbopack X, with desorption at 290 °C for 10 min and 40 mL/min flow, provided optimal recovery and sensitivity for VOCs and PAHs. This work provides a validated and efficient approach for multibed thermal desorption, improving chromatographic performance and analytical reliability in complex environmental matrices.