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1 (i.e., those with m/z >250) can be attributed to somewhat heavier oxygen derivatives of diterpenes and triterpenes. In generał, the ions corresponding to certain truncated entities can be recognized in Figs l(a)-(c) and as an example, one can point out to the m/z values equal to 60, 121 and 152. These data provide certain information about the Chemical naturę of the compounds of origin, although they do not sufFice for proper identification.

Figs l(b) and (c) show the mass spectra of the remaining two fractions (2 and 3), with lesser affinity to the adsorbent than fraction 1. Their respective compositions are simpler than that of fraction 1, which can be deduced from the less numerous signals in the former two spectra than in the latter one. Fractions 2 and 3 can largely be the mixtures of some heavier terpenes and some lighter terpenoids. The ions corresponding to certain truncated entities can also be recognized in Figs l(b) and (c). For example, in Figs l(b) and (c) we again repeatedly encounter signals with the m/z values equal to 121.23 and 151.22 (the latter one being the predominant signal in fractions (b) and (c)), although in these cases, the compounds of origin most probably differ from those giving rise to the identical mass values in Fig. l(a).

Low-Temperature Thin-Layer Chromatography-Liąuid Chromatography with

Mass Spectrometric Detection (LT TLC-LC-MS)

Indirect mass spectrometric fingerprinting of the essential oil fractions preliminarily separated by means of TLC (see bands (1 )-(3) in Fig. l(o)) was carried out with use of high-performance liquid chromatograph coupled with mass spectrometric detector. Each band was eluted by means of the TLC-MS interface to the high-performance liquid chromatographic system and further its constituents underwent the second-step separation on the HPLC column. As the essential oils originating from the Salvia genus (and morę specifically, from Salvia lavandulifolia) contain many terpenes and terpenoids, one can expect groups of isomers among them, which cannot easily be separated with use of a universal (i.e., a non-specific) liquid chromatographic system and which, moreover, fumish identical m/z values for the ions derived from one and the same group of isomers. Consequently, even using the 2D LT TLC-LC-MS system to the fingerprinting of the investigated essential oils, one cannot expect fuli separation of the compounds contained in bands (l)-(3) from the densitogram (Fig. l(o)) to the individual Chemical species, but further fractionation to the chemically closer related sub-groups only.

In Figs 2-4, we showed the fingerprinting results obtained with use of the 2D LT TLC-LC-MS system for the mixtures of compounds contained in bands (l)-(3), respectively,