BUCHI Encapsulator B-395 Pro - Manual (Page 59)

6 Operation
59 B-395 Pro Operation Manual, Version C
6. As soon as the bead chain is stable, move the collection cup out of the way of the liquid jet to
start the actual bead production process. The bead stream should disperse 3 to 10 cm (approxi-
mately 1” to 4”) below the electrode. An optimal distance is about 5 cm (2”) below the electrode.
To achieve this goal you will need to adjust the electrostatic tension and possibly slightly fine tune
the vibration frequency and pumping speed.
7. Note and record the exact process parameters. Inspect the actual bead production in the light of
the stroboscope lamp to verify the settings.
8. Shortly before the syringe plunger is fully depressed, move the collection cup of the bypass back
into the bead stream. This will prevent that large droplets, which are formed at the end of the
production process, contaminate the homogeneous collection. Stop the pump. Turn off the elec-
trostatic dispersion unit and the vibration control system. Or press "home" to move back the arm
of the syringe pump. This will also deactivate the electrostatic dispersion unit and the vibration.
9. Let the beads harden for 5 minutes.
10. To drain the hardening solution from the reaction vessel, slowly open the drain clamp so that it will
take 1 to 2 minutes to drain 500 mL. Turn off the magnetic stirrer when about ¾ of the liquid has
drained. Close the drain clamp as soon as the liquid level reaches the settled beads.
NOTE
Always leave the beads slightly covered with solution to prevent clumping.
11. Fill the bottle of the liquid transfer set with 400 mL of washing solution and pump it into the reac-
tion vessel. Restart the magnetic stirrer as soon as the magnetic stir bar is covered with liquid
so the beads are not damaged. Wash the beads for 5 minutes and then drain off the liquid as
described above (item 10).
12. Pump in the final 200 mL of washing solution into the reaction vessel. Re-suspend the beads by
turning on the magnetic stirrer.
13. Open the bead collecting valve and let the beads flow into the bead collecting flask. If beads
remain in the reaction vessel, let liquid flow back from the bead collecting flask into the reaction
vessel by raising the bead collecting flask higher than the reaction vessel drain. Re-suspend the
remaining beads with this liquid and transfer it back into the bead collecting flask by lowering it
below the reaction vessel..
14. Close the silicone tube from the reaction vessel to the bead collecting flask with the clamp.
Disconnect the bead collecting flask from the reaction vessel and check the beads for quality
under a microscope.
15. Immediately after the end of the bead production process fill a syringe with distilled water, attach it
to the bead producing unit and flush the nozzle to avoid having the polymer dry and clogging the
system thus creating a maintenance problem. Clean the reaction vessel thoroughly, including the
various in and out ports.