Sub-ppb Level Detection of BTEX Gaseous Mixtures with a Compact Prototype GC Equipped with a Preconcentration Unit.

Irene Lara-Lbeas,Stéphane Colin,Vincent Person,Lucien Baldas,Alberto Rodríguez-Cuevas,Christina Andrikopoulou,Stéphane Le Calvé

doi:10.3390/mi10030187

Abstract

In this work, a compact gas chromatograph prototype for near real-time benzene, toluene, ethylbenzene and xylenes (BTEX) detection at sub-ppb levels has been developed. The system is composed of an aluminium preconcentrator (PC) filled with Basolite C300, a 20 m long Rxi-624 capillary column and a photoionization detector. The performance of the device has been evaluated in terms of adsorption capacity, linearity and sensitivity. Initially, PC breakthrough time for an equimolar 1 ppm BTEX mixture has been determined showing a remarkable capacity of the adsorbent to quantitatively trap BTEX even at high concentrations. Then, a highly linear relationship between sample volume and peak area has been obtained for all compounds by injecting 100-ppb samples with volumes ranging from 5–80 mL. Linear plots were also observed when calibration was conducted in the range 0–100 ppb using a 20 mL sampling volume implying a total analysis time of 19 min. Corresponding detection limits of 0.20, 0.26, 0.49, 0.80 and 1.70 ppb have been determined for benzene, toluene, ethylbenzene, m/p-xylenes and o-xylene, respectively. These experimental results highlight the potential applications of our device to monitor indoor or outdoor air quality.

Highlights

In recent years, there has been an increasing interest in air pollution since numerous studies have demonstrated its impact on human health [1,2,3]
Numerous experiments were conducted to evaluate the performances of the gas chromatographs (GC) prototype: (1) ANbruemaketrhoruosuegxhpeexripmereinmtsenwtewreacsocnadrruiecdtedoutot wevitahluaahteigthheBpTeErXfocromnacnecnetsraotfiotnheoGf 1Cppprmotointyopred:e1r)tAo dbreetearkmthirnoeutghhe aedxpsoerrpimtieonntcwapaascictayrroifedtheouptrewcoitnhceanhtriagthorBiTnEtXhecsotnucdeinedtractoinodnitoiof n1s;p(p2m) reipneoatradbeirlittyo wdeatseirnmviensetigthaeteadd; s(3o)rpthtieosnamcapplaecvitoyluomf tehveaprireedcoinnctehnetrraantogrei0n–t8h0emsLtufdoireda ficoxenddigtiaosneos;u2s)croenpceeanttarbaitliiotny owfaBsTEinXv;easntdig(a4t)etdh;e 3g)astehoeussBaTmEpXlecovnocelunmtraetiovnarvieadriedinbetthweeernan0g–e1000–p8p0b fmorLa fgoirvean sfaimxepdlegvaosleuomues. concentration of BTEX; and 4) the gaseous BTEX concentration varied between 0–100 ppb for a given 3sa.1m
We reported the development of a compact GC prototype for near-real time BTEX analysis in sub-ppb range

Summary

Introduction

There has been an increasing interest in air pollution since numerous studies have demonstrated its impact on human health [1,2,3]. Most of these instruments perform BTEX analysis in less than 15 min providing high-resolution concentration-time profiles. Only the GC-metal oxide semiconductor (MOS) reported by Zampolli et al [22] and the GC- photoionization detector (PID) developed by Skog et al [23] were able to detect concentrations below 1 ppb.

Results

Conclusion