Determination of synthetic pharmaceuticals in phytotherapeutics by capillary zone electrophoresis with contactless conductivity detection (CZE-C4D)

In this work, a method for simultaneous determination of amfepramone, fenproporex, sibutramine and fluoxetine was developed by capillary zone electrophoresis with capacitively coupled contactless conductivity detection ((CD)-D-4) using a homemade capillary electrophoretic system. The optimized conditions for the separation of the pharmaceuticals by CZE were as follows: 50 mmol L-1 phosphate buffer (pH 5.0) in 50/50 (v/v) mixture of water/acetonitrile as the working electrolyte, 15 kV separation voltage, 25 degrees C separation temperature, hydrodynamic injection by gravity using 20 cm injection height and 60 s injection time. The detection by C4D was carried out by using a homemade detector, which employs a sinusoidal wave generator operating at 600 kHz frequency and 2 V-pp, wave amplitude. The optimized and validated CZE-(CD)-D-4 method was applied for the determination of the studied pharmaceuticals as adulterants in phytotherapeutic formulations commercialized in Brazil for slimming purposes. (C) 2010 Elsevier By. All rights reserved.