Sensitive determination of monoterpene alcohols in urine by HPLC-FLD combined with ESI-MS detection after online-solid phase extraction of the monoterpene-coumarincarbamate derivates

A method was developed for the determination of the monoterpene alcohols verbenol, myrtenol, perillyl alcohol, alpha-terpineol, Delta(3)-carene-10-ol, thymol and p-alpha,alpha-trimethylbenzylalcohol in urine samples. After an enzymatic cleavage of their glucuronide- and sulfate conjugates the monoterpene alcohols were converted in the urine matrix with 7-diethylaminocoumarin-3-carbonylazide into monoterpene-[7-(diethylamino)-coumarin-3-yl]-carbamate derivates prior to analyses. Enrichment of the monoterpene alcohols from the urine matrix was achieved by online-solid phase extraction (SPE) with restricted-access material (RAM). After removal of excess derivatization reagent and urine matrix components. the monoterpene derivatives were separated by high-performance liquid chromatography (HPLC) in combination with fluorescence (FLD) detection and simultaneous mass spectrometric (MS) identification. Detection limits (LOD) for studied monoterpene alcohols ranged between 22 and 197 ng/L. The method was validated and successfully applied to urine samples from human subjects orally exposed to monoterpenes trough an intake of cough medication containing monoterpenes as active medicinal ingredients. Published by Elsevier B.V.