Heart-cutting two-dimensional gas chromatography in combination with isotope ratio mass spectrometry for the characterization of the wax fraction in plant material

•The paper describes a new configuration allowing 2-dimensional GC in combination with IRMS.•The configuration is based on capillary flow technology and a Deans switch system.•The 2D-GC–IRMS allows to analyze resolved peaks in complex matrices.•Accurate and reproducible delta values were obtained.•The set-up allows to distinguish compounds based on the C-pool used for their synthesis.

Gas chromatography coupled to isotope ratio mass spectrometry after on-line combustion (GC–C-IRMS) and high temperature conversion (GC–HTC-IRMS) is used for compound specific isotope ratio determination. This determination can only be performed successfully if the target solutes are fully resolved from other compounds. A new instrumental set-up consisting of heart-cutting two-dimensional GC based on capillary flow technology and a low thermal mass GC oven in combination with an isotope ratio mass spectrometer is presented. Capillary flow technology was also used in all column and interface connections for robust and leak-free operation. The new configuration was applied to the characterization of wax compounds in tobacco leaf and corresponding smoke samples. It is demonstrated that high accuracy is obtained, both in the determination of δ13C and δ2H values, allowing the study of biosynthesis and delivery mechanisms of naturally occurring compounds in tobacco.