CEM liberty - Preparing Deprotection Solution; Preparing Capping Solution

Liberty
™
Automated Microwave Peptide Synthesizer
600178 • Revision 5 • October 2009
47
To use bulk amino acids:
Weigh out the appropriate amount of the amino acid as calculated using the 1.
Usage and Reagent Calculators.
Transfer the amino acid to a clean 125 mL plastic bottle.2.
Add the appropriate volume of DMF to the bottle.3.
Place a cap on the bottle and shake vigorously to ensure the amino acid has fully 4.
gone into solution.
Preparing Deprotection Solution
Measure out the appropriate amount of deprotection reagent as calculated using 1.
the Usage and Reagent Calculators.
Transfer the deprotection reagent to a 1 L clear glass bottle.2.
Add the appropriate volume of DMF to give the correct nal volume as calculated 3.
in the Reagent Calculator.
Add HOBt if necessary.4.
Place a cap on the bottle. Swirl the bottle gently to ensure the deprotection 5.
reagent (and HOBt, if used) has fully gone into solution.
Preparing Capping Solution
Capping is optional, and is not necessary for most routine syntheses. The capping bottle
does not need to be in place unless capping is being used in the method(s) being run. CEM
recommends using 0.5 M acetic anhydride in DMF with 0.125 M DIEA and 0.015 M HOBt. To
prepare capping solution:
Determine the total volume of capping solution needed using the Usage 1.
Calculator.
Calculate the amount of acetic anhydride needed. Measure out the appropriate 2.
amount and transfer to a 1 L glass bottle.
Use the reagent calculator to determine the volume of DIEA and mass of HOBt 3.
required. Measure out the appropriate amount of each and add to the acetic
anhydride.
NOTE
If the amino acid is to be used on one of the external positions, instead
transfer it to a 50 mL centrifuge tube.
NOTE
For sequences susceptible to aspartimide formation, CEM recommends
the addition of 0.1 M HOBt to the deprotection solution as this signicantly
reduces levels of aspartimide. The appropriate mass of HOBt can be
calculated in the Reagent Calculator under the Activators tab. Enter the
total volume of deprotection and change the concentration to 0.1, then click
Calculate.