QUANTITATIVE-ANALYSIS OF THE VOLATILE CONSTITUENTS OF LEMON PEEL OIL - EFFECTS OF SILICA-GEL CHROMATOGRAPHY ON THE COMPOSITION OF ITS HYDROCARBON AND OXYGENATED FRACTIONS

Fifty-one constituents accounting for congruent-to 99.7% of total volatiles common to both Sicilian and California commercial lemon peel oils have been identified and quantitified in a single GC capillary run. The quantification was performed by using both internal standard and appropriate response factors, which are necessary for accurate volatile analysis and simultaneous determination of nonvolatiles. Direct comparisons to results obtained by using area percent or internal standard only show the advantage of using response factors. Fractionation of the oils by open-column silica chromatography facilitated identification of constituents and improved the accuracy of the analysis. Yields of the fractions recovered from the column were usually greater than 96%. The reactivity of high-quality silica gel with lemon hydrocarbons was investigated, and while quantitative effects are small, several oxygenates are formed on the column. Use of a cold (3-degrees-C) column significantly reduces the amount but not the number of oxygenates formed.