Development of a novel portable miniaturized GC for near real-time low level detection of BTEX

This paper reports on the development and optimization of a miniaturized GC/PID system dedicated to BTEX monitoring in near-real time conditions at ppb level. The system consists of a 6-ports valve, a capillary column and a mini-photoionization detector (PID), its final weight is around 4 kg. The system operates at very low flow rate (lower than 4 mL min(-1)) irrespective of the carrier gas used. The device is controlled through homemade software which provides instrument control and real-time chromatograms collection. The system's performance was studied and optimized with two different carrier gases, namely hydrogen and nitrogen. The optimal experimental conditions of BTEX separation was determined according to the calculated H.E.T.P. and the total analysis time for a single run which was set to a maximum of 10 min. Using the optimal conditions, the detection limit, stability and repeatability of the analytical system were assessed. A detection limit of 1 ppb was found for benzene and toluene with both carrier gases and less than 3 ppb for other compounds of the family. A slight advantage in terms of separation was found with hydrogen especially for ethylbenzene and xylenes using the defined experimental conditions. (C) 2015 Elsevier B.V. All rights reserved.