Oka H, Uno K, Harada K, Yasaka K, Suzuki M
J Chromatogr. 1984 Aug 31;298(3):435-43. doi: 10.1016/s0021-9673(01)92741-4.
An isocratic high-performance liquid chromatographic method for the determination of tetracyclines is described using a mobile phase containing oxalic acid and C8- and C18-modified silica gel columns. For good separations of tetracyclines, oxalic acid concentrations of above 0.01 and 0.2 M respectively for parent tetracyclines (group I) and impurities in tetracycline (group II) are required. The optimum pH of the aqueous oxalic acids solution in the mobile phase is 2.0. The combinations of the C8-modified silica gel column with methanol-acetonitrile-0.01 M aqueous oxalic acid solution pH 2.0 (1:1.5:5) and the C18-modified silica gel column with methanol-acetonitrile-0.2 M aqueous oxalic acid solution pH 2.0(1:1:3.5) gave satisfactory results for groups I and II, respectively.
描述了一种用于测定四环素的等度高效液相色谱法，该方法使用含有草酸的流动相以及C8和C18改性硅胶柱。为了实现四环素的良好分离，母体四环素（I组）和四环素中的杂质（II组）分别需要草酸浓度高于0.01 M和0.2 M。流动相中草酸水溶液的最佳pH值为2.0。C8改性硅胶柱与甲醇 - 乙腈 - 0.01 M pH 2.0的草酸水溶液（1:1.5:5）以及C18改性硅胶柱与甲醇 - 乙腈 - 0.2 M pH 2.0的草酸水溶液（1:1:3.5）的组合分别对I组和II组给出了满意的结果。
