Application of homemade portable gas chromatography coupled to photoionization detector for the detection of volatile organic compounds in an industrial park

Abstract

Traditional offline detection of volatile organic compounds (VOCs) requires complex and time-consuming pre-treatments including gas sampling in containers, pre-concentrations, and thermal desorption, which hinders its application in rapid VOCs monitoring. Developing a cost-effective instrument is of great importance for online measurement of VOCs. Recently, photoionization detectors (PID) are received great attention due to their fast response time and high sensitivity. This study a portable gas chromatography coupled to PID (pGC-PID) was developed and optimized experimental parameters for the application in online monitoring of VOCs at an industrial site. The sampling time, oven temperature and carrier gas flow rate were optimized as 80 s, 50 °C and 60 ml·min⁻¹, respectively. The sampling method is direct injection. Poly tetra fluoroethylene (PTFE) filter membranes were selected to remove particulate matter from interfering with PID. The reproducibility and peak separation were good with relative standard deviations (RSD) ≤ 7%. Good linearities of 27 VOCs standard curves were achieved with R² ≥ 0.99, and the detection limits were ≤10 ppb with the lowest being 2 ppb for 1,1,2-Trichloroethane. Finally, the pGC-PID is successfully applied in online VOCs monitoring at an industrial site. A total of 17 VOCs species was detected and their diurnal variations were well obtained, indicating pGC-PID is well suited for online analysis in field campaign.