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Lyophilization of cotton leaves

Lyophilization of cotton leaves

  1. Freeze cotton leaves sample at -70 C in a deep freezer.
  2. Transport the sample in an ice chest box.
  3. Check to see that drain plug is closed (left side of condenser) and be sure that <break> switch is off and ballast open.
  4. Turn on bottom <cool> switch of the condenser.
  5. Turn on top <pump><cool><control> switches of chamber and set "shelf temperature control" to -400 or -50 C. Then, wait for chamber temperature to drop to set level (it usually takes 1 to 3 hr).
  6. Turn on bottom <pump> switch.
  7. Place the frozen samples on trays. Arrange in even layers. Placing second layer of tubes in bottom 2 trays is OK). It may be fun to place the probes into samples to watch the changing temperature.
  8. Close the chamber and wait for 1 to 2 minutes till the samples and chamber temperature equalize. During this time, ice crystals will coat metal parts of the chamber.
  9. Turn on <gauge> switch and close ballast, and wait for vacuum to reach <100 mT (about 5 to 10 min). In the mean time, condenser temperature should be at least -40 C.
  10. Set "shelf temperature control" to -20 C and let run for 3 hr at least or overnight.
  11. Check the condenser periodically to be sure that the coil has not collected enough ice to lug it up (rarely a problem on a fresh run).
  12. After the run is complete, turn off <gauge> switch and open ballast.
  13. Turn on <break> and turn off vacuum <pump> switches simultaneously.
  14. Remove the samples and turn off top <pump><cool><control> switches.
  15. Turn off <break> switch.
  16. Close the cap of samples tightly immediately.
  17. Place samples in dry, air tight environment as soon as possible and store out of direct sunlight.

* Lyophilizer is accessible in Bldg 11(Rm 104). If any problem happens, check with G. Lazo. Reserving the freeze-dryer by placing a note (Stating name, time length of lyophilization) on the machine several days before your schedule would be best.