Purification Each cycle of synthesis begins with removal of a trityl protecting group from the 5' end of the growing oligonucleotide. When the final base is coupled to the oligonucleotide, the trityl group is left attached and so is present on full-length oligonucleotides only, not on shorter synthesis byproducts. The trityl protecting group is removed from the full-length oligonucleotide during purification. For most applications, oligonucleotides can be used directly, without further purification or solvent exchange. Because these electronic requisitions are interpreted by parsing programs developed at the facility, it is essential to follow the standardized format carefully.
Instructions are available from the facility upon request.
Delay and Turnaround Queuing of requisitions is set by the DNA synthesis research assistant, following a policy designed to maintain efficiency and fairness. The instrument operates on a 24-hour cycle and once started cannot be interrupted. Requisitions received by 12 p.m. will often be completed the following day. We can synthesize and purify 75 oligonucleotides in about 24 hours, provided the oligonucleotide lengths are 24 bases or shorter. Longer sequences extend the run times to 48 hours or more.