Easy-to-manufacture micro gas preconcentrator integrated in a portable GC for enhanced trace detection of BTEX

Abstract

Air pollution is a current environmental and global public health issue, which requires technological developments to monitor airborne pollutants such as Volatile Organic Compounds (VOCs). These organic species are dangerous for humans even at trace levels.In this regard, an analytical device can be advantageously coupled with a preconcentration system to improve its sensitivity. In this context, a novel preconcentrator was conceived, manufactured, and tested inside an existing portable gas chromatograph (GC). With a very limited gas sample of 20 mL, the limits of detection achieved are 0.057, 0.150, 0.368, 0.396, 0.418 ppb for benzene, toluene, ethylbenzene, m-/p-xylenes and o-xylene, respectively. These values enable the system to monitor air quality even in the environments with the strictest regulation (0.6 ppb for benzene). Besides, the comparison with the literature demonstrates that the present analytical device is from two to three orders of magnitude more sensitive than the previous ones when detection limit is expressed in pg.The repeatability and reproducibility experiments show that the measurements are reliable and stable over time, while maintaining a reasonable time resolution of 19 min which can be easily reduced to 15 min by a full automation. Moreover, the average power consumption of the system was limited to 61 W allowing the system to work autonomous and battery powered. Finally, this preconcentrator can be conveniently fabricated without the need for a cleanroom and the simplicity of the design provides an easy way to replace the adsorbent broadening the range of VOC that can be detected.