There can be many causes of excessive back pressure but one very common cause is build up of foreign materials on the top of the HPLC Column. This situation can result when sample precipitates (retains or accumulates) or dust and other particles from the degradation of the pump seals.

This situation can be avoided by the use of a guard column; when you reach excessive back pressure, simply replace the guard column.

It is strongly recommended to use the low cost Cogent Column Filters that are disposable and easy to use to protect your columns.