Analysis free monoterpenes

However, these workers have noted the ability of monoterpene dlols and triols, which are also present In musts and wines, to act as precursors of volatiles (6) Accordingly, variations In monoterpene abundance between samples could be reflective of the method used in preparing the sample or of the analysis Itself. A similar questioning of the emphasis given to the analytical characterization of grapes and wines based on quantification of free monoterpenes had been expressed previously when the lability of various precursor forms of these compounds was first recognized (18,19). Nevertheless these caveats questioned only the detailed interpretation of the statistical data and the need for appropriate techniques to avoid artefact formation. The fundamental soundness of the correlations remains intact. 

Analysis of free monoterpenes. The review of Terrier and Boidron (2) summarized a range of analytical techniques including gas and silica gel chromatography, for determination of free monoterpenes. Schreier et al. (35) employed an initial fractionation of extracts on silica gel, followed by gas chromatographic analysis. 

The GCxGC resolution advantage is known to improve the efficiency of enantioselective essential oil analysis (in contrast to one-dimensional analysis). In a single temperature-programmed analysis, the individual antipodes of optically active components can be separated and are effectively free from matrix interferences. The enantiomeric compositions of a number of monoterpene hydrocarbons and oxygenated monoterpenes in Australian tea tree Melaleuca alternifolia), including sabinene, a-pinene, (3-phellandrene, limonene, trans-sabinene hydrate, ds-sabinene hydrate, linalool, terpinen-4-ol, and a-terpineol shown in Figure 7,... 

---