Generally, liquid chromatography columns are directional and can only pass through the mobile phase according to their specified flow direction, especially when the filling quality of the chromatography column is not high. For example, self-made chromatography columns in the laboratory, using chromatography columns with ultra-high pressure, etc

. The inlet end of such chromatography columns generally has a certain depression. If used in reverse, it can cause the packing of the chromatography column to collapse, resulting in reduced column efficiency and other consequences. But if a well prepared chromatographic column, such as a thermoelectric chromatographic column, can be backwashed to flush out impurities after entering a relatively dirty sample, but this is not recommended in the operating manual.

So, if the quality of the column is good, theoretically wood has an impact, but it is not recommended; If the quality of the column is poor, it may lead to a decrease in separation and column efficiency.