摘要：Alkaloids were extracted from a sample of ephedra with ammoniacal ether, transferred into acid solution, and diluted to a certain volume. Aliquots of this test solution were reacted under heating with ninhydrin in the presence of ascorbic acid and pyridine. The intensity of the color developed was measured at the maximum absorbancy peak at 570 mμ. Alkaloid content was calculated from the regression line, subtracting the blank from the observed value. It was found that this method was hardly interfered by amino acids and ammonium salt present in ephedra, through a control test with the quantity of these acids and salt about several times as much as those contained in ephedra. For further check of the comparative accuracy and precision of this method of analysis, several sets of analytical data were evaluated. The results of estimation made according to this proposed procedure agreed well with those obtained by the method of Japanese Pharmacopoeia VI and their reproducibility was satisfactory.
