Photoionization-ion mobility spectrometer for non-targeted screening analysis or for targeted analysis coupling a Tenax TA column

Abstract

Photoionization-ion mobility spectrometer (UV-IMS) can be used as a screening instrument to distinguish gasoline vapors from other similar samples, obtaining characteristic fingerprints in a quick and simple analysis. A non-targeted approach can be used to resolve many problems, moreover, this device can also be used for targeted analysis. In this case a Tenax TA trap was connected to the UV-IMS as a pre-separation step in order to identify compounds present in the gasoline gaseous sample, such as benzene and toluene. Firstly, target analytes were trapped in a Tenax TA column at ambient temperature and then they were desorbed thermally in an oven and connected to the UV-IMS for their analysis. Instrumental parameters such as temperature ramp, sample gas flow rate, drift gas flow rate, adsorption time and adsorption flow rate were optimized to obtain high sensitivity, selectivity and precision to determine benzene and toluene in vapour gaseous samples. The UV-IMS was calibrated with standard gases generated in an exponential dilution flask, obtaining a limit of quantification of 1.8 and 1.9 mg m-3 for benzene and toluene, respectively. The method developed was successfully applied to identify these analytes in air samples close to a gasoline spillage