Find solutions to product related issues. For unlisted issues please contact local Cytiva service representation.

General Advice for Troubleshooting when Using Cross Flow Filters

Please check the following items during troubleshooting:

Samples volume and system working volume have been used in calculations of concentration factor and diafiltration beforehand.

Process settings of Membrane Capacity, Flux, Shear (or volumetric cross flow rate) have been properly applied for both sample characteristics and membrane pore size or NMWC designation.

Filter is properly wetted before use (also make sure that there is no air lock in the filters created by condensation on microfiltration membranes as a result of incorrect autoclave settings).

Ensure CFF filters are properly wetted before starting processing. This may be tested against new cartridge “Clean Water Flux Test or against the water flux specifications in the Certificate of Quality. Microfitlration membranes are shipped dry and are rewetted with water or buffer. Hollow fiber ultrafiltration membranes are shipped in glycerol wetting preservative. These filters may require 15-20% alcohol/water solution to restore wetting or remove glycerol. Flat sheet cassette ultrafiltration devices (for example, KvickLab and KvickFlow Cassettes) are shipped in a solution of NaOH/Glycerol which must be flushed out before use.

Prior to using cassettes, make sure the single gasket is in the correct position in the holding device and that the cassette(s) within are oriented properly in the holder.

Check integrity of cassette system using water under pressure on retentate side to 1 barg to check for leaks in the seal of the cassette with the stainless steel holding device.

Check to see that cartridges or cassettes that have been previously used are checked for integrity (air diffusion or bubble point tests) and for cleanliness (normalized Clean Water Permeability before processing).