A highly sensitive and selective silicon-based micro-analytical prototype was used to identify a few ppb of volatile organic compounds (VOCs) in indoor air. Herein, a new non-activated tannin-derived carbon synthesized by an environmentally friendly method, DM2C, a MIL-101(Cr) MOF and a DaY zeolite were selected for the preconcentration of BTEX compounds (i.e. benzene, toluene, ethylbenzene and xylenes). Integrating a small amount of these nanoporous solids inside a miniaturized preconcentration unit led to excellent preconcentration performance. By taking advantage of the high adsorptiondesorption capacities of the DM2C adsorbent, concentrations as low as 23.5, 30.8, 16.7, 25 and 28.8 ppb of benzene, toluene, ethylbenzene, ortho-and para-xylene, respectively, were detected in a short analysis time ( 10 min) even in the presence of 60 % relative humidity at 25 °C. The DM2C showed excellent stability, over a period of 4 months and more than 500 tests, as well as repeatability, which makes it a very reliable adsorbent for the detection of trace VOCs in indoor air under realistic conditions in the presence of humidity.