One of the causes of a gradual increase of a column pressure after each sample injection is that fine particles in the sample clog the frit of the column. Replacing the column frit is one solution; however it is more convenient to use precolumn filter. Connect a precolumn filter between the injector and the column, check the line pressure occasionally, and replace the precolumn filter when the line pressure increases. Stainless steel precolumn filters are suitable for stainless steel tubing systems. Both PEEK and stainless steel precolumn filters are suitable for PEEK tubing systems.
High-molecular weight compounds (proteins, DNA, sugars, etc.) that easily and irreversibly adsorb to the main columnare likely to cause a pressure increase and separation failure. When these compounds adsorb to the main column, it is difficult to recover column performance by cleaning. A guard column will protect the main column when fouling of the main column is due to contamination from sample matrices.