Can Increased Instrumental Sensitivity Replace Extensive Sample Preparation?

The optimization of gas chromatographic separations is often a necessary step to push the limits of detection and quantitation to their utmost limits. Parameters controlling injection and separation conditions need to be adjusted and optimized thoroughly for rugged and reproducible conditions. Thereby, careful attention needs to be paid to the sample preparation stage, since it often enhances the instrumental sensitivity. Moreover, sample preparation is highly prone to error, as well as time-consuming[1]. For this reason, techniques that offer a reduction of the overall sample preparation procedure are of increasing interest.
Two-dimensional comprehensive gas chromatography (GC×GC) offers a wide scope of advantages allowing for simplified sample preparation. For example, analytes of interest can be separated from the interfering matrix due to the increased separation capacity, while the cold zone compression allows for increased sensitivity and improved peak shapes. Especially the hyphenation of GC×GC and highly sensitive mass analyzers can potentially reduce steps needed in existing sample preparation procedures.
In this study, the authors evaluate the performance of a GC×GC-ToF/MS for a detailed analysis of the volatile organic profile in Belgian chocolate. To evaluate the impact of the MS’s sensitivity a previously established sample preparation procedure was compared to a minimalistic sample preparation approach [2]. Although the majority of compounds could be determined in both approaches, initial findings indicate differences in between the two investigated approaches. Thereby, the differences are not only limited to the total number of compounds detected but also the detected compound classes differ within the compared approaches. Depending on the analytical challenge, the applied approach has to be chosen.
References:
[1] R.E. Majors, Overview of Sample Preparation, LCGC. (1991) 16–20. http://www.chromatographyonline.com/overview-sample-preparation.
[2] C. Müller, F. Vetter, E. Richter, F. Bracher, Determination of caffeine, myosmine, and nicotine in chocolate by headspace solid-phase microextraction coupled with gas chromatography-tandem mass spectrometry, J. Food Sci. 79 (2014). doi:10.1111/1750-3841.12339.