Performance and characteristics of a trace gas analyzer for the determination of volatile organic compounds in air

Abstract

AbstractAn instrument has been developed and tested for the continuous measurement of volatile organic compounds (VOC) in air. The system consists of a gas chromatograph equipped with a dedicated sampling device that allows the sample to be transferred to a cooled microtrap via sampling loops (10, 100, 250 ml) or via a direct pump transfer to the trap. The microtrap is placed in the chromatographic oven just below a modified split‐splitless injector, allowing direct liquid injection for calibration of the system; the injector is in communication with the sampling valve equipped with the loop and the sampling pump. The system allows 24‐hour sampling and analysis of a large number of VOC (up to 25 individual hydrocarbons ranging from C2C9) and also polar volatile organic compounds PVOC. Thanks to the particular trap geometry, a minimum consumption of liquid nitrogen (between 150300 ml) is needed for each analytical run and no water managing system is normally required for humid air samples.