Simultaneous Determination of Six Adulterants in Functional Foods by High Performance Liquid Chromatography with Diode Array Detection

Objective To establish a method for simultaneous determination of six adulterants including norpseudoephedrine (NPE), pseudoephedrine (PSE), amfepramone (AMF), strychnine (STR), fenfluramine (FEN) and sildenafil (SIL) in functional foods by high performance liquid chromatography with diode array detection (HPLC-DAD). Methods Food samples were treated with 2% formic acid ultrasonically, and then the extracts were cleaned-up with solid phase extraction (SPE) with strong cation exchange cartridges (SCX). The sample solution was separated on a C₁₈ column with the mobile phase composed of 0.05 mol/L potassium dihydrogen phosphate (pH3.0) and acetonitrile. The qualitative analysis was accomplished with spectral and retention times of the chromatographic peaks. The external standard curves were established for quantification of the adulterants. Results The linear correlation coefficients of the 6 chemicals were greater than 0.999. The intraday RSDs were 6.25%-8.19% and the interday RSDs were 6.61%-10.8% with the average recoveries of 80.5%-110.0%. The detection limits of the method were 15.9-66.5 μg/kg. Conclusion The method is simple, sensitive and inexpensive and is suitable to the determination of the 6 chemicals in functional foods.