Hydrocarbon oil type analysis using the blank tube FI method and msRepeatFinder
Introduction
The blank‑tube FI (Field Ionization) method introduces a sample into the GC inlet, passes it through a blank tube, and detects it by FI soft ionization. This method enables detection of molecular ions in less than one minute. When hydrocarbon mixtures such as oils are analyzed, complex mass spectra containing multiple molecular ion peaks are obtained. For analysis of such spectra, Kendrick mass defect (KMD) analysis in the polymer analysis software msRepeatFinder is effective. In addition, msRepeatFinder Ver.9 newly implements a hydrocarbon type analysis function, enabling simpler and more convenient oil analysis. In this MSTips, three hydrocarbon oils—crude oil, diesel oil, and pyrolysis oil—were analyzed. Carbon number‑DBE plots obtained by hydrocarbon type analysis are explained, and the characteristic features of each sample derived from the analysis results are introduced.