Quantitative analysis of characteristic aroma components in rose hydrosol by reversed-phase liquid chromatography using hydroxypropyl-β-cyclodextrin as mobile-phase additive

Quantitative determination of eight characteristic aroma components, namely, benzyl alcohol, phenylethyl alcohol, eugenol, geraniol, nerol, linalool, citronellol, and methyl eugenol, by reversed-phase high-performance liquid chromatography with hydroxypropyl-β-cyclodextrin as mobile-phase additive was investigated. The proposed method was validated and demonstrated with good linearity of 0.994 to 1.000 with a recovery in the range of 94.97-109.38% and exhibited favorable accuracy, intra and inter-day precision based on relative standard deviation values. Additionally, the inclusion complex between eight characteristic aroma components and hydroxypropyl-β-cyclodextrin was investigated, the complex formation was found at a 1:1 molal ratio for eight characteristic aroma components and hydroxypropyl-β-cyclodextrin, and the apparent formation constant between citronellol and hydroxypropyl-β-cyclodextrin was determined to be 71.86 M-1. In those components, ∆H of linalool and citronellol was found to be +877.03 kJ mol-1 and +1433.67 kJ mol-1, and ∆S were positive, which indicated that transfer from mobile phase to the stationary phase of the two analytes was entropically driven. Furthermore, this method was successfully applied to determination of characteristic aroma components in Rosa damascena Mill. hydrosol and R. rugosa cv. "Plena" hydrosol, in which it was found that phenylethyl alcohol, citronellol, and methyl eugenol were principal components.