Determination of salicin and related compounds in botanical dietary supplements by liquid chromatography with fluorescence detection.

A sensitive and reliable method is described for quantitative determination of salicin (including salicyl alcohol) and salicylic acid in botanical dietary supplements by reversed-phase liquid chromatography (LC) with wavelength-programmed fluorescence detection. One gram sample material was extracted with 20 mt aqueous phosphate buffer (pH 5.0), which was heated in an 80 degrees C water bath for 30 min. After centrifugation and cooling of the extract to room temperature, the supernatant was diluted with additional buffer. A 1 mt portion of diluted extract was mixed with 1 mt beta-glucosidase solution (2 mg/mL) and incubated for 40 min in a 37 degrees C water bath. The extract was passed through a 0.45 mu m syringe filter and analyzed by LC. Limits of quantitation for salicin and salicylic acid were 20 and 1 mu g/g, respectively. Recoveries from samples fortified with salicin at 20, 100, and 1000 mu g/g and with salicylic acid at 5, 20, and 50 mu g/g ranged from 85 to 110%, with standard deviations less than 7%.