[Determination of twelve elements in ephedrine extraction by microwave digestion-AAS].

The sample digested by microwave are of some merits: simple, rapid, saving agents, nonpollution and being easily digested. Microwave-digested sample with HNO3-H2O2 and AAS method were established for the determination of Fe, Ca, Mg, Zn, Mn, Cu, Na, K, Ni, Cd, Pb and Cr in ephedrine extraction. In this paper, the selection of digestion conditions, including pressure, power, acids and time of digestion was evaluated. According to standard sample GBW08501 Tea-leaves, we checked the method accuracy and precision. The accuracy values are in the range of 91.1%-105%. The RSDs of flame atomic spectrometry and graphite furnace atomic spectrometry are in the range of 0.2%-2.3% and less than 7%, respectively. The results are very consistent with the the reference values. It proved that the method has satisfactory precision and accuracy. The proposed method is simple, rapid, of nonpollution and safe. It was has been applied to the determination of trace elements in ephedrine extraction and provided useful data for production in factory.