Promises of a new versatile field-deployable sorbent tube thermodesorber by application to BTEX analysis in CH4

Novel field-portable high-pressure adsorbent tube sampler prototype for the direct in situ preconcentration of trace compounds in gases at their working pressures: application to biomethane

“…5 and 6 present relatively high standard deviations due to the poor nCx-TD repeatability which was demonstrated in previous work. 38 In 5 (2 L N sampled at different pressures) and Fig. 6 (5 L N sampled at different pressures), no effect of the gas sampling pressure on the preconcentration of the 41 HVOC on the TA14-CpX29 MAT could be established between 5 and 100 bar a when the gas circulates through the MAT and as long as the MAT are not saturated.…”

“…Multibed adsorbent tubes (MAT), whose theoretical working principle is explained in the ESI, † were self-assembled and conditioned as described in previous work. 38 Briefly, empty amber glass tubes (ID 4.8 mm, L 44 mm, ActionEurope, Sausheim, France) are manually packed with commercial adsorbents from Supelco, Bellefonte, PA, USA ( Table 1 ). The MAT held 14 ± 0.2 mg Tenax®TA (front bed) and 29 ± 0.2 mg Carbopack™X (back bed) and are further called ‘TA14-CpX29’.…”

“…After packing, tubes are conditioned at 320 °C during 8.5 h under a continuous clean N 2 flow as described earlier. 38 The Tenax®TA conditioning temperature (320 °C) was used to condition the MAT as conditioning them at the higher Carbopack™X conditioning temperature (350 °C) would lead to irreversible thermal degradation of TA. As soon as the conditioning sequence is completed, tubes are sealed with aluminum crimp caps with PTFE/silicone/PTFE septa (11 mm, high temperature ultra-low-bleed silicone, ActionEurope) and stored until utilization in individual hermetic polyethylene zip bags in a larger zip bag in a desiccator at 4 °C as recommended by (ref.…”

“…Each MAT is placed in the thermodesorber in the reverse direction as compared to the gas sampling direction. The nCx-TD prototype was presented in previous work 38 and the chromatographic peak resolutions, limits of detection and repeatabilities obtained with this TD-GC-MS analytical chain have also been presented in (ref. 38 ).…”

“…The nCx-TD prototype was presented in previous work 38 and the chromatographic peak resolutions, limits of detection and repeatabilities obtained with this TD-GC-MS analytical chain have also been presented in (ref. 38 ). Note the 200 °C temperature programmed in the nCx-TD corresponds to an effective desorption temperature of 300 °C inside adsorbent tubes.…”