Flavour&Fragrance analysis: Easy heart cut MDGC with mass spectrometric detection in 1st and 2nd dimension

Significance of the Topic

The analysis of flavours and fragrances often involves highly complex mixtures in which isomeric and enantiomeric compounds critically influence aroma, quality control, and authenticity. Advanced separation techniques are therefore essential to distinguish overlapping compounds, detect adulteration, and confirm geographic or botanical origin.

Objectives and Study Overview

This application note describes a rapid and reproducible method for multidimensional gas chromatography (MDGC) with heart-cut switching and combined flame ionization (FID) and mass spectrometric (MS) detection. The study focuses on the enantiomeric profiling of key terpenes in commercial lavender oil, demonstrating the technique’s ability to resolve chiral components without derivatization or extensive sample preparation.

Instrumentation

• Shimadzu GC-2010 equipped with flame ionization detector for first-dimension separation
• Shimadzu GCMS-QP2010 Plus for second-dimension mass spectral detection
• Multi Deans Switch MDGC-2010 for precise heart-cut transfer without altering first-column pressure
• Polar Carbowax capillary pre-column (30 m × 0.25 mm × 0.25 μm) coupled to a chiral RTX capillary analytical column (30 m × 0.25 mm × 0.25 μm)
• FID-MS capillary split interface to allow simultaneous detection in the first dimension

Methodology

Commercial lavender oil was injected directly onto the polar pre-column. Pre-defined retention time windows were heart-cut via the MDGC switch into the chiral column for enantiomeric separation. The first-dimension FID signal was used to set cut positions and perform area normalization. In standby mode, the system delivered an FID chromatogram without transfer, enabling method setup. During heart cuts, 100 % of target fractions were routed to the second dimension. A pressure-driven split/shutoff mechanism controlled whether the FID-MS split line remained open or blocked, ensuring clear distinction between first- and second-dimension data streams.

Main Results and Discussion

The multidimensional GC/GC-MS configuration achieved baseline resolution of major monoterpenes sabinene, β-pinene, and limonene in three successive heart cuts. Simultaneous FID and MS detection in the first dimension exhibited retention time alignment within 0.01 minute and an approximate 1 : 15 split ratio. Enantiomeric analysis of linalool showed a dominant single isomer in lavender oil, consistent with a natural source. In contrast, a commercial peach aroma displayed nearly equal proportions of both linalool enantiomers, indicating synthetic origin.

Benefits and Practical Applications

• Enhanced separation power for co-eluting and chiral compounds without derivatisation
• Efficient method development by visualizing uncut FID chromatograms and defining cut windows interactively
• Simultaneous quantitation (FID) and identification (MS) in the first dimension
• Reliable authentication of essential oils, flavours and fragrances in quality control and fraud detection

Future Trends and Applications

Advances may include automated multidimensional methods for broader compound classes, integration with high-resolution MS for structural elucidation, and machine-learning algorithms for deconvolution of complex chromatograms. Expansion to on-site or portable MDGC systems could facilitate in-field authentication of natural products.

Conclusion

The described MDGC heart-cut approach with dual FID/MS detection provides a robust, user-friendly platform for chiral and complex mixture analysis. Its capacity to transfer entire target fractions, combined with seamless pressure control, supports high recovery and accurate enantiomeric quantitation, making it highly valuable for flavour, fragrance, and quality assurance laboratories.

Reference

[1] L. Mondello, A.C. Lewis, K.D. Bartle, "Multidimensional Chromatography," 2002, pp. 217–223
[2] S. Böhme, H.U. Baier, "Easy Heart-cut MDGC with Mass Spectrometric Detection in 1st and 2nd Dimension," LC×GC Applications Book, July/August 2009, pp. 31–32
[3] Shimadzu Application Note SCA-180-017, "Introduction of MDGCsolution"