Tangential flow filtration ( TFF ) concentration of phytoplankton
Get Vivaflow catridge out of storage Mount Vivaflow catridge as Fig .
1 ( image de C . Brussaard ) in open circuit .
Remove the clamps Set the pump to maximum speed .
Manometer should be at about 2.5 bars ( with a new cassette sometimes the manometer get stuck , if the value is too low there is a leak in the system ) .
Rinse the cartridge with about 250 mL of MilliQ water ( longer is cartridge has been stored in ethanol ) .
Replace MilliQ water by sample in 6 L bottle .
Take sample for flow cytometry to compute concentration factor .
Rinse cartridge with about 250 mL of sample .
Put the retentate line into the sample bottle ( Fig . 2B - Recirculation mode ) .
Record sample volume and start pump increasing to macimum speed .
Clamp the retentate line to increase filtrate flow so that Manometer gets up to 2.5 bars .
Concentrate sample until about 250 mL remains ( 6 L takes about one hour ) .
Transfer sample to a smaller bottle ( 250 mL ) then finally to a 50 mL tube with conical bottom .
Continue to concentrate very carefully , lowering the pump speed until the sample volume is reduced to 15 - 20 mL .
When final volume is about 10 mL , clamp filtrate tube and recirculate slowly ( no change of volume should take place ) .
Leaving the filtrate tube clamped , get the feed line out of the sample in order to get back the total volume of concentrated sample .
Take sample for flow cytometry count ( to compare with original sample concnetration and estimate concentration factor ) .
Store concentrated sample for later use ( e . g . flow cytometry sorting , culture etc . . . ) .
Go back to Fig . 1 configuration ( Open circuit ) .
Rinse 1 min with filtered sea water .
Rinse 1 min with distilled water .
Rinse with 50 mL NaOH 0.1 M .
Put all three tubes ( feed , retentate , filtrate ) in bottle containing NaOH 0.1 M .
Recirculate for 20 min ( to get rid of everything on the cartridge filter ) .
Rinse with 250 mL of MilliQ water ( Fig . 1 ) .
Stop the pump and clamp all three tubes .
Store at 4°C .
For a storage beyond 1 day , store with Ethanol 10 %
