Purification of vetiver alcohols and esters for quantitative high-performance thin-layer chromatography determination in Haitian vetiver essential oils and vetiver acetates

摘要

A simple, fast, and efficient High-Performance Thin-Layer Chromatography (HPTLC) method was developed for the simultaneous quantitative determination of alcohols and acetates in Haitian vetiver essential oils (Chryzopogon zizanioides) and its acetylated form. Analytes were separated by using a mixture of n-hexane-chloroform-ethyl acetate (8:6:0.5, v/v/v) as mobile phase under 47% humidity. Quantification was achieved by densitometric evaluation of the analytes in absorbance mode under visible light (λ=530nm) after staining with a vanillin-sulfuric acid reagent. Reference mixtures of alcohols and acetates were obtained by fractionation of Haitian vetiver oil or vetiver acetates, followed by purification of the fractions of interest by means of Over-Pressured Layer Chromatography (OPLC). The chemical composition of each reference fraction was determined by using GC-MS and GC×GC-MS, and their overall purity was determined by GC/FID and HPTLC. The TLC method provided compact spots for alcohols (R _(f2)=0.18±0.01 and R _(f1)=0.28±0.01) and acetates (R _(f3)=0.65±0.01). Calibration plots showed good linear correlation with r ~2=0.9995±0.0001 and r ~2=0.9995±0.0001 for alcohols and r ~2=0.9996±0.0001 for acetates in a 40-200ngspot ~(-1) concentration range with respect to peak areas. The method was validated for precision and accuracy. Limit of detection (LOD) and quantification (LOQ) were determined. Method specificity was confirmed using retention factor (R _f) and GC-MS control of the standards reference mixtures.