Method for detecting impurity K in ganciclovir and method for separating impurity

The invention discloses a method for detecting an impurity K in ganciclovir and a method for separating the impurity. The method comprises the following steps: detecting a test solution containing ganciclovir by adopting high performance liquid chromatography, wherein a chromatographic column adopted by the high performance liquid chromatography is a cation exchange chromatographic column, mobile phases comprise a mobile phase A and a mobile phase B, and the mobile phase A is a phosphoric acid aqueous solution containing 0.012 M ammonium dihydrogen phosphate, in the phosphoric acid aqueous solution, the volume percent of phosphoric acid is 0.12%, the mobile phase B is acetonitrile. In combination with a specific elution mode, the method not only can realize effective separation and detection of the impurity K, but also can completely elute other known impurities, and is beneficial to the service life of a chromatographic column. 本发明公开了一种更昔洛韦中杂质K的检测方法、及杂质的分离方法，其包括如下步骤：采用高效液相色谱检测含更昔洛韦的供试品溶液；所述高效液相色谱采用的色谱柱为阳离子交换