How to Choose Liquid Chromatography Protection Column
The loading method of the protective column is also very important. At present, there are protective columns for film filling method, which is easy to use and can be dry-loaded in the laboratory. However, its biggest drawback is that it is not economical, especially for the specific situation in China, where the relative cost of one-time use is relatively high. In addition, the chromatographic packings filled with the membrane packing method have limited chromatographic packing and can only provide very limited protection; however, because of the small amount of packed chromatographic packing and the shorter length of the guard column, the retention time of the analytical sample is also limited. The impact is also very small.
Another kind of guard column structure essentially shortens the chromatographic analysis column, and the design method is direct-connected/push-tight or monolithic. The monolithic design is based on the column manufacturer directly installed on the chromatographic column and must be ordered together with the chromatographic column. It can be used very conveniently but cannot be modified. Direct connection design The connection can be installed at any time by the chromatographer, it can be used with any brand of the column, and the length of the guard column can be chosen according to the sample. The hand-tight guard column is structurally the same as the direct-connection guard column, but it can be directly tightened by hand without using tools such as a wrench. In addition, from the perspective of the guard column structure, the guard column structure is further divided into whether the guard column core can be replaced. Now, most of the guard columns can replace the core, which can reduce the use cost of the guard column.
Most people choose the packing of the guard column according to the packing of the chromatographic column. Under normal circumstances, the same chromatographic packing as the analysis column can be selected. However, depending on the actual analytical work, it is not necessary to exactly match the packing of the analytical column.
The principle for choosing the guard column is: Under the premise of meeting the requirements of the separation analysis, try to select the shorter guard column as much as possible, and try to select the filler with small retention of the sample as much as possible.