Quantitative Determination of Geosmin in Red Beets (Beta vulgaris L.) Using Headspace Solid-Phase Microextraction

An improved analytical method for the determination of geosmin in red beets was developed using headspace solid-phase microextraction (HSPME). Volatiles of beet juice were extracted in headspace for 2 h using a polydimethylsiloxane/divinylbenzene fiber, thermally desorbed from the fiber, and analyzed by gas chromatography. The HSPME method was determined to be suitable for geosmin analysis as evidenced by high relative recovery (99.2%), low relative standard deviation (7.48%), and reasonable detection limit (1 μg/kg of beet root tissue). The concentrations of geosmin in four beet cultivars ranged from 9.69 ± 0.22 to 26.7 ± 0.27 μg/kg, depending on cultivar. Keywords: Geosmin; headspace solid-phase microextraction (HSPME); purge-and-trap; red beets (Beta vulgaris L.)