Structure Elucidation Using Gas Chromatography−Infrared Spectroscopy/Mass Spectrometry Supported by Quantum Chemical IR Spectrum Simulations

Abstract

An improved strategy for compound identification incorporating gas chromatography hyphenated with Fourier transform infrared spectroscopy and mass spectroscopy (GC− FTIR/MS) is reported. (Over)reliance on MS may lead either to ambiguous identity or to incorrect identification of a compound. However, the MS result is useful to provide a cohort of possible compounds. The IR result for each tentative compound match was then simulated using molecular modeling, to provide functional group and isomer differentiation information, and then compared with the experimental FTIR result, offering identification based on both MS and IR. Several basis sets were evaluated for IR simulations; Def2-TZVPP was a suitable basis set and correlated well with experimental data. The approach was applied to industrial applications, confirming the isomers of 2,3-bis(thiosulfanyl)-but-2-enedinitrile, bromination products of 1-bromo-2,3dimethylbenzene, and autoxidative degradation of phenyl-di-tert-butylphosphine.

Foods and Contaminants Analysis Using Multidimensional Gas Chromatography: An Update of Recent Studies, Technology, and Applications

“…MS offers useful molecular and fragment ion m / z data, although specificity toward some individual molecules (e.g., isomers) is lacking . This may be overcome by hyphenation with Fourier transform infrared spectroscopy (FTIR). , Alternatively, GC may be hyphenated with selective detectors such as the electron capture detector (ECD), nitrogen phosphorus detector (NPD), and flame photometric detector (FPD) to provide a measure of elemental specificity. Multiple detectors may be used in combination to improve compound identification, as noted for reported applications below, such as parallel detection (splitting the column effluent to multiple detectors) or as separate analyses.…”

Profiling Olefins in Gasoline by Bromination Using GC×GC-TOFMS Followed by Discovery-Based Comparative Analysis

“…Numerous methods have been reported for olefin analysis, including infrared spectrometry (IR), supercritical fluid chromatography, and NMR . Hyphenated GC-spectroscopic techniques, such as GC with vacuum ultraviolet detection (GC-VUV) and GC-IR, are promising for olefin profiling due to the selectivity in both the ultraviolet and infrared regions for double bonds. Recently, GC stationary phases containing silver ions to selectively separate olefins have been developed. , Although these phases are not yet commercially available, they appear to be very promising for application to complex petrochemical samples.…”