Hello Mike We have been using pall filters on our FACSVantage SE with Tubosort for about 18 months now with only rare instances of sort contamination. We sort with pressures up to 45 psi We have left the pall filter on for up to six months without problems. We check for sterility daily by sorting into nutrient broth. When we install a new pall filter we add a couple of liters of 70& ethanol to the sheath tank and run it through the whole system (including filter) for at least a hour to overnight. We then rinse with sterile water followed by sheath fluid. We try to keep the sheath tank sterile at all times. The outside of the tank is washed with ethanol before opening and filled only with sterile filtered sheath fluid (PBS with Hepes). We prepare 10 liters of sheath fluid at a time using Millipore Sterivac 0.22µm filters into autoclaved 1 gallon containers. To prevent bacteria from working their way in from the front end of the system we do a 10-15 minute hydrogen peroxide rinse each morning. We disconnect the quick release fitting after the pall filter and cover the exposed end with a ethanol filled latex finger cut off a glove. Attach a quick release fitting to a syringe. We then push 50cc of 5% hydrogen peroxide through the system, making sure to set the fluidics control knob to all it's positions. Also make sure the syringe used to chase air out fills with peroxide. The idea is to get the peroxide in contact with all surfaces after the pall filter. When done just reconnect the pall filter and rinse till the peroxide is cleared. Good Luck Rich Schretzenmair Cancer Center Flow Cytometry Shared Resource University of Pennsylvania
This archive was generated by hypermail 2b29 : Sun Jan 05 2003 - 19:01:42 EST