Methodological aspects: Gas Chromatographic-Mass Spectrometric Analysis of Essential Oil of Siberian fir

Abstract

The article is devoted to the compounds identification problem for complex mixtures of organic substances of natural origin by the example of Siberian fir essential oil. Natural essential oil components by using the gas-liquid chromatography on a non-polar phase capillary column HP-5ms was experimentally separated within the various temperature-programming modes. Chromatograms reported by the total ion current were used for identification of component peaks by mass spectrometry in the ChemStation program with the NIST11 mass spectrometer library. The result of the work are the conditions for the chromatographic separation of components of Siberian fir essential oil, which allow to detect all representative and characteristic components of a mixture of terpene compounds specified in GOST ISO 10869-2015. Examples of mass spectra of limonene and β-fellandrene show the possibilities and features of chromatography-mass spectrometry as an identification method for compounds of similar structure in the case of overlapping chromatographic peaks. Here is described an example of a mass spectrum of a high-similarity library sylvestrean mass spectrum, which is, however, the result of the addition of mass-spectrum lines of a pair of components (limonene, β-fellandrene). The effect of the initial chromatographic temperature (temperature range from 50 ° C to 120 ° C) on the degree of separation of the investigated components pair was researched. It is shown that under experimental conditions, with an increase in the initial temperature up to 85 ° C, the sufficient separation of components is achieved in order to correctly identify the corresponding peaks in the automatic integration mode of the chromatogram with a quantitative evaluation of their content in the sample. An increase in the initial temperature above 90 ° C leads to a deterioration in the quality of the chromatogram. By the the result of the current paperwork, the conditions of carrying out of chromatography-mass-spectrometric analysis were selected, which allowed to reliably identify 13 characteristic components of a mixture of Terpenes of Siberian fir essential oil.