Sample injection of aromatic compounds from passive concentrators into multicapillary column by the thermal desorption method

Abstract

At present, there is an increased interest in geochemical methods of searching for hydrocarbon deposits by detecting on the Earth's surface the scattering halos of hydrocarbons that migrated from those deposits, namely the aromatic hydrocarbons such as benzene, toluene, xylenes. The concentrations of the migrated hydrocarbons on the surface of the Earth are usually low and could only be detected at the threshold level of the gas analyzers. Therefore, for their registration, the preconcentration is applied, in particular, the passive preconcentration. For this purpose, the concentrators are used, which are laid at shallow depths in the explored area. The survey technology that is being developed by the authors uses the reusable concentrators in the form of hollow stainless-steel tubes with SE-30 siloxane-based sorbent applied on their inner surface. The concentrators placed in the analytical containers are laid in the ground for 1-2 days. The analysis of the samples from the concentrators is carried out on a portable multicapillary gas chromatograph in the field conditions. The current article is devoted to the development of a special device for the sample injection from the passive concentrators and the experimental determination of the optimal mode of thermal desorption sample injection from the concentrators into the multicapillary column. The original injection scheme is given, where the gas-dynamic isolation of the injection device camera and the multicapillary column during the concentrator heating and sample analysis is implemented; the optimum concentrator heating time and the optimum sample injection time are determined. Keywords: passive concentrators, thermal desorption sample injection, gas-dynamic isolation of the injection device and column DOI: http://dx.doi.org/10.15826/analitika.2019.23.3.003 (Russian) V.M. Gruznov 1,2,3 , M.N. Baldin 1 , A.O. Malysheva 1,3 1 Trofimuk Institute of Petroleum Geology and Geophysics of Siberian Branch of Russian Academy of Sciences, Koptug Avenue, 3, Novosibirsk, 630090, Russian Federation 2 Novosibirsk State University, Pirogova St., 2, Novosibirsk, 630090, Russian Federation 3 Novosibirsk State Technical University, Prospekt K. Marx Avenue, 20, Novosibirsk, 630073, Russian Federation