We have used 1 H and 13 C NMR spectroscopy to analyze the chemical composition of essential oils of pine needles grown in different regions of the Republic of Belarus. We consider the change in the composition of the oils depending on the area where the pines were grown. We suggest using pine essential oil as a biological indicator of environmental conditions. Introduction. Forest ecosystems in the Republic of Belarus, which predominate in the ground cover, have important recreational and environment-modifying functions and are the main source of raw material for the lumber industry. Pine forests occupy the greatest area among forested pieces of land. A characteristic feature of coniferous tree species is their biosynthesis of essential oil: a complex mixture of organic compounds, the major compounds in which are volatile monoterpene hydrocarbons.Chromatographic methods are preferably used today for monitoring the composition and quality of essential oils [1,2]. Despite the universality of these methods, in order to obtain reliable results in analysis of complex mixtures in chromatography, we need to use columns with different packings and to have on hand the pure components of the analyte mixtures, which increases the analysis time. High resolution NMR spectroscopy does not have these disadvantages. Modern spectrometers have high sensitivity and allow us to analyze complex compositions on different nuclei in sufficiently short time intervals, yielding reliable results.Many publications have been devoted to chromatographic analysis of the composition of pine needle essential oil from pines grown in different regions of the world, the effect on its composition from climate, where it is grown, light-dark cycles, seasonal and geographical variations, age, the part of the top of the tree sampled, the time at which the samples were taken, and technogenic factors (see, for example, [3][4][5][6]). However, the composition of pine essential oil from pines in different areas of Belarus has not been studied, except for Minsk forestry stands [3, 4]. We have not been able to find papers devoted to application of NMR spectroscopy for studying the composition of pine needle essential oil.The aim of this work was to use NMR to analyze pine needle essential oils from pines grown in areas of the Republic of Belarus with different environmental conditions. Experimental procedure. The samples were taken in the vicinity of the cities Narovlya, Rechitsa, Dobrush, Lel'chitsy, and Ostrovets. The samples of tree greens were taken in natural pine forests from 20-40-year old trees in the fall and winter months (the period of maximum essential oil content in the needle) [5]. Each sample was placed into a labeled bag and polyethylene packages to avoid losses of the most volatile components. From the needle samples, using the procedure suggested in [6] we made up a combined sample from 35-40 trees, which we used to carry out the subsequent experiments. The essential oils were separated by steam distillation and the quantitative yield was
