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

Characterizing trace compounds in gaseous matrices such as natural gas is challenging owing to the low concentrations and intricate interactions between present. In contrast whole sampling methods, direct situ with preconcentration of on adsorbent tubes followed by thermal desorption chromatography coupled mass spectrometry (TD-GC–MS) a powerful method enabling screen unknown targeted detection limits where moreover sample transfer associated loss contamination risks are avoided. Here, new versatile, field-deployable thermodesorber prototype (‘nCx-TD’, nCx Instrumentation, Garlin, France) fitted self-assembled purpose-built Tenax TA presented. Its GC-injection performances investigated using 10 ppmv BTEX CH4 synthetic contrasting results those obtained solid phase microextraction (SPME) injection gas. Unlike most commercial thermodesorbers, nCx-TD characterized fast “plug” without re-focusing trap, leading high chromatographic peak resolutions. Between closely eluting ethylbenzene m- p-xylene isomers, Gaussian resolution at concentration was 2.9 while that SPME respectively 1.7 1.9. The nCx-TD-obtained resolutions increased significantly (1 ppmv) SPME- remained constant level across tested. A real sampled through analyzed via TD-GC–MS nCx-TD. More than 50 distinct were detected, opening exciting perspectives tube multibed configurations field analysis field-portable GC's.