title: Enantiomeric analysis of (+)-menthol and (-)-menthol by fluorogenic derivatization and liquid chromatography.
abstract: A simple and sensitive liquid chromatography is described for the quantitative analysis of enantiomeric (+)-menthol and (-)-menthol that are lack of chromophore. The method is based on the derivatization of (+)-menthol and (-)-menthol with a fluorescent reagent, naproxen acyl chloride, in toluene. The resulting diastereomic derivatives were separated on a C8 column with methanol-water-tetrahydrofuran (80:18:2, v/v) as a mobile phase; they were sensitively monitored with a fluorimetric detector (excitation 235 nm and emission 350 nm). The linear range for the quantitation of the enantiomers was 5.0-50 microM with a detection limit (signal to noise ratio = 3, injected volume 10 microl) of about 1 microM. Application of the method to the enantiomeric analysis of menthol in mint plants proved simple and feasible. Toluene was used for the extraction of menthol from the leaves of mint, and the resulting toluene extract was directly used for subsequent derivatization without solvent replacement.
authors.affiliation: Graduate Institute of Pharmaceutical Sciences, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Lin
authors.forename: Hsing-Lung
authors.initials: HL
authors.lastname: Wu
authors.forename: Hwang-Shang
authors.initials: HS
authors.lastname: Kou
authors.forename: Shou-Mei
authors.initials: SM
authors.lastname: Wu
authors.forename: Su-Hwei
authors.initials: SH
authors.lastname: Chen
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005240:Feasibility Studies; D005456:Fluorescent Dyes / Q000737:chemistry*; D013058:Mass Spectrometry; D008610:Menthol / Q000032:analysis* / Q000737:chemistry; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence; D013237:Stereoisomerism
chemical_list: D005456:Fluorescent Dyes; D008610:Menthol