The chemical analysis and quality control of both Piper methysticum G. Forster (kava-kava) and extracts obtained by aqueous acetone or aqueous methanol as well as supercritical fluid extraction are reviewed. In the last two decades various procedures concerning the separation and detection of kavalactones have been routinely carried out by gas chromatography (without previous derivatization of kavalactones) and high performance liquid chromatography but most of them are not validated or only partially validated. Recently, analyses by supercritical fluid chromatography and micellar electrokinetic chromatography have also been reported. Both gas chromatography and high performance liquid chromatography can be used for the analysis of kavalactones with some advantages and disadvantages for each method. Using gas chromatography analysis, methysticin and yangonin, which are two of the major components, are generally not separated. In addition, the high temperature of the injection port caused the decomposition of methysticin. Concerning high performance liquid chromatography analyses, the reversed-phase is generally better because highly reproducible with a very low detection limit for all compounds even if the quantitative analysis of the kavalactones by liquid chromatography needs to be carried out in the absence of light to prevent the cis/trans isomerisation of yangonin.

Mixed systems containing fluorocarbons (FC) phase separate below certain temperatures. The liquidliquid coexistence curves show upper critical solution temperatures (T c ) that depend on the nature of the components. In this work, we report the phase separation measurements of mixtures obtained from shortchain linear perfluoroalkanes (perfluorohexane, perfluoroheptane, and perfluorooctane) with some n-alkanes, cyclohexane, benzene, ethers, and chlorinated solvents. The results are discussed in terms of the chemical nature and polarizability of the components.

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