Liquid chromatographic determination of dehydroepiandrosterone (DHEA) in dietary supplement products

A liquid chromatographic (LC) method was developed to assess the potency of products that contain dehydroepiandrosterone (DHEA), a precursor hormone synthesized from cholesterol by the human adrenal cortex and converted to potent androgens and/or estrogens in peripheral tissues. Forty-five commercial products (both single and multi-ingredient) were subjected to analysis by the proposed method. A Zorbax Rx C18 column with a mobile phase containing acetonitrile-0.025 M phosphate buffer (60 + 40), pH 3.50, and UV detection at 292 nm was used for 87% of the products. An alternative mobile phase containing methanol-0.025 M phosphate (75 + 25), pH 3.50, was used to isolate DHEA from more complex product mixtures. Assay values varied from 0 to 109.5% of the declared amount with an overall mean value of 91.1%. The recoveries based on fortified products ranged from 96.4 to 101.2%, and the intraday precision (RSD, n = 5) varied from 0.50 to 1.66%.