HS-SPME-GC-MS for the Quantitation and Chiral Characterization of Camphor and Menthol in Creams

A GC-MS method is proposed for the analysis of camphor and menthol in "over-the-counter" (OTC) products. Sample preparation was achieved by head-space solid phase microextraction using a polydimethylsiloxane fibre. GC analysis was performed using a Phenomenex ZB-5 column and a temperature program was adopted. The method was validated by studying linearity (range 0.1-15.0% w/w), accuracy, reproducibility and sensitivity. Applications were directed to the determination of the active ingredients in four different OTC-products; the mean recoveries were in the ranges 91.30-99.74% and 94.34-102.89% for camphor and menthol, respectively and the LOD was in the order of 0.005% (w/w). Other important terpenoids (alpha- and beta-pinene, 1,8-cineole, menthone, isomenthone, alpha-terpineole, t-cinnamaldehyde, eugenole) were identified by mass spectra and Kovats retention indices and quantified by peak area normalization to 100%. Further information for a comprehensive characterization of the OTC-products was achieved by the GC chiral analysis on a Cyclosil B capillary column.