a column used for high speed liquid chromatography which is characterized in eminent separating ability suitable for microanalysis while having a small internal diameter , minimizing the separation impediment due to minute flaws , tiny recesses or the like on the inner surface thereof , and facilitating packing operation of particulate packing or support material thereinto , by enabling the material to closely contact not only with each other but also with the inner surface of the column that can yield to a necessary extent .