High efficiency liquid chromatography techniques coupled to mass spectrometry for the characterization of mate extracts

There is growing interest related to rapid screening and full characterization of the constituents of plants with medicinal properties; among these, "Mate" or Yerba Mate is a tea-like beverage widely consumed in South America, obtained from the dried leaves of Ilex paraguariensis. The high content in polyphenols accounts for in vitro and in vivo antioxidant activity of the extracts obtained from this plant; on the other hand, the high complexity of the samples extracted, depending on the method employed, may preclude complete resolution by conventional HPLC techniques. For this purpose, a comprehensive two-dimensional liquid chromatography (LC x LC) system, comprised of an RP-Amide first dimension and a partially porous octaclecylsilica column in the second dimension, has been compared with a one-dimensional system. The latter was operated using a partially porous octadecylsilica Column, with diode array(DAD) and electrospray/ion trap-time of flight(ESI/IT-TOF) detection for the most complex extracts. The employment of the hybrid mass spectrometer allowed unequivocal identification of several compounds in the mate extracts. Using LC x LC-MS3, it was possible to discriminate between congeners of chlorogenic acids, along with monoacyl- and diacylchlorogenic acid esters. (C) 2009 Elsevier B.V. All rights reserved.