Minor Base Bottle Change Procedure

For ABI 390 Series Synthesizers

When minor base amidites are loaded on an ABI synthesizer using the bottle change procedure ~400 µl of amidite solution are consumed in the prime step. A manual procedure can be used to load minor bases with a minimal loss of amidite (~200 µl). This procedure uses the manual control mode on the ABI synthesizer and timed delivery of the reagents to change minor bases.

1. Transfer ~3.0 ml anhydrous ACN to a clean, dry amidite bottle.
2. Remove the old amidite bottle from the "5" position. Wipe the line and put the amidite bottle containing ACN onto position 5.
3. Rinse line 5 with ACN and Argon as follows.

   Function	Function Type	Time (sec)
   1	Block Flush	5
   64	18 to waste	10
   54	5 to waste	30
   64	18 to waste	10
   74	18 to 5	10
   10	Flush to 5	10

4. Remove the rinse bottle from position 5. Wipe the line and put the vial containing the amidite to be used on the synthesizer in position 5.

   Function	Function Type	Time (sec)
   10	Flush to 5	10
   101	Phos. Prep	15
   54	5 to waste	1 (use timed delivery)
   64	18 to waste	10
   1	Block flush	10

5. Start synthesis. Do not use begin cycle.