Detection of Sodium Caprylate in Human Serum Albumin by Precolumn Derivation Reversed Phase High Performance Liquid Chromatography

A method was developed for the determination of sodium caprylate in human serum albumin by reversed phase high performance liquid chromatography (RP-HPLC) after pre-column derivatization. The caprylic acid, extracted from human serum albumin by hexane, was treated with omega-bromoacetophenone and 18-crown-6 for 30 min at 50 degrees C, and analyzed on a Nova-Park C(18) (150 mm x 3.9 mm, 4 rim) column with methanol-water (75:25, V/V) as the mobile phase. The internal standard was enanthic acid, the flow rate was 1.0 mL/min and the detection wavelength was 262 nm. The extraction yield of caprylic acid was 97.9% and that of enanthic acid was 98.2%. The linear range of sodium caprylate was 9.00 x 10(-4) - 1.44 x 10(-2) mol/L (r = 0.9995). The average recovery of caprylic acid was 99.7%, RSD was less than 0.9%. The present method is reliable and relatively simple and can be used for the determination of sodium caprylate in human serum albumin.