Rapid comprehensive characterization of crude oils by thermogravimetry coupled to fast modulated gas chromatography–single photon ionization time-of-flight mass spectrometry

Comprehensive multi-dimensional hyphenation of a thermogravimetry device (i.e. a thermobalance) to gas chromatography and single photon ionization–time-of-flight mass spectrometry (TG–GC×SPI–MS) has been used to investigate two crude oil samples of different geographical origin. The source of the applied vacuum ultraviolet radiation is an electron beam pumped rare gas excimer lamp (EBEL). The soft photoionization favors the formation of molecular ions. Introduction of a fast, rapidly modulated gas chromatographic separation step in comparison with solely TG–SPI–MS enables strongly enhanced detection especially with such highly complex organic matrices as crude oil. In contrast with former TG–SPI–MS measurements, separation and identification of overlying substances is possible because of different GC retention times. The specific contribution of isobaric compounds to one mass signal is determined for alkanes, naphthalenes, alkylated benzenes, and other compounds. Figure Specific characteristics of a two-dimensional TG–GC×SPI–MS contour plot obtained from Turkish crude oil. The complete m / z and TG temperature ranges are displayed in a . The magnified region from m / z 50–250 and 140–170 °C reveals the “pixilated” structure ( b ). Parts c and d reveal the system’s ability to investigate compounds in a broad m / z range with limitations for very-high and very-low boiling compounds as shown for m / z 260 and m / z 70, respectively