Analysis of small molecules and metabolites

Marina Creydt

The analysis of small organic molecules (sometimes also referred to as metabolomics) like lipids or other biomolecules can be approached with numerous investigation methods. These include, on the one hand, vibrational spectroscopic methods based on IR or Raman spectroscopy. Such methods are non-invasive, but have only a limited resolving power.

On the other hand, high-resolution methods such as DART-MS and LC-MS (Xevo G2-XS QTof, Ion Mobility Q-TOF), GC-MS or NMR can also be used. With such methods, it is possible to detect and also to identify individual molecules. However, in most cases such procedures require invasive or at least minimally invasive sampling.

The analysis of small molecules can help clarify numerous questions. For example, it is possible to identify organic dyes, to determine geographical origins or to analyse production methods. As with proteomics analyses, meta-experiments can also provide information about the lifestyle or the traditions of the authors or readers. In addition, information about possible storage influences can be obtained.

However, it must be kept in mind that for many scientific questions reference samples with known metadata must be available in order to classify the "unknown" samples (see also section “provenance studies”).

Result of an LC-MS analysis of a wood sample to determine the geographical origin with help of different lipids classes. The chromatographic separation of the LC is shown on the x-axis. The m/z ratio, which was determined with the mass spectrometer, is plotted on the y-axis. The spots in the plot each represent an analyte signal. The colour code reflects the intensity of the signal. In this way approx. 2500 analytes could be detected. By means of multivariate analysis methods, similarities and differences in various samples can be recognized (Creydt et al. 2021; Creydt et al. 2022).

References

Mass Spectrometry Equipment
Creydt, M. and Fischer, M. (2023). Artefact Profiling: Panomics Approaches for Understanding the Materiality of Written Artefacts. Molecules, 28, 12, 4872. https://doi.org/10.3390/molecules28124872
Creydt, M., Ludwig, L., Köhl, M.l, Fromm, J., and Fischer, M. (2021). Wood profiling by non-targeted high-resolution mass spectrometry: Part 1, Metabolite profiling in Cedrela wood for the determination of the geographical origin, J. of Chrom. A, 1641, 461993. https://doi.org/10.1016/j.chroma.2021.461993
Creydt, M., Lautner, S., Fromm, J., and Fischer, M. (2022). Wood profiling by non-targeted liquid chromatography high-resolution mass spectrometry: Part 2, Detection of the geographical origin of spruce wood (Picea abies) by determination of metabolite pattern, J. of Chrom. A, 1663, 462737. https://doi.org/10.1016/j.chroma.2021.462737
Manfredi, M., Robotti, E., Bearman, G., France, F., Barberis, E., Shor, P., Marengo, E. (2016). Direct analysis in real time mass spectrometry for the nondestructive investigation of conservation treatments of cultural heritage. J. Anal. Methods Chem. 2016, 6853591. https://doi.org/10.1155/2016/6853591
Newton, J., Ramage, G., Gadegaard, N., Zachs, W., Rogers, S., Barrett, M.P., Carruthers, G., and Burgess, K. (2018). Minimally-destructive atmospheric ionisation mass spectrometry authenticates authorship of historical manuscripts. Sci. Rep., 8, 10944. https://doi.org/10.1038/s41598-018-28810-2
Sharma, D., Singh, M.R., and Dighe, B. (2018). Chromatographic study on traditional natural preservatives used for palm leaf manuscripts in india. Restaur. Int. J. Preserv. Libr. Arch. Mater., 39, 249–264. https://doi.org/10.1515/res-2018-0005
Zilberstein, G., Zilberstein, R., Zilberstein, S., Maor, U., Cohen-Ofri, I., Shor, P., Bitler, T., Riestra, B., and Righetti, P.G. (2021). Proteomics and metabolomics composition of the ink of a letter in a fragment of a dead sea scroll from cave 11 (P1032-Fr0). J. Proteom., 249, 104370. https://doi.org/10.1016/j.jprot.2021.104370