Determination of ephedra alkaloids by high-performance liquid chromatography

Two simple methods were developed for the simultaneous determination of six alkaloids (ephedrine, pseudoephedrine, norephedrine, norpseudoephedrine, m ethylephedrine and methyl-pseudoephedrine) in Ephedrae Herba by high-perfor mance liquid chromatography. The first method was carried out by using a Co smosil 5C(18)-MS column with a gradient solvent system consisting of a phos phate buffer and acetonitrile, and detection at 210 nm. The contents of alk aloids in non-pretreated ephedra herb extracts could be determined easily i n 50 min. Alternatively, the alkaloids could be determined within 35 minute s by using a Cosmosil 5C18-MS column with an isocratic solvent system of a sodium dodecyl sulfate - acetonitrile solution. The two methods are compare d and discussed.