For each synthesis cycle, up to 1 to 2 % of free 5'-hydroxy groups remain after the phosphoramidite coupling step has been completed. By running a subsequent "Capping" step using an anhydride, these free hydroxyl groups are converted to acetates and are hindered from further chain elongation and formation of long oligonucleotides with incorrect sequences. For optimal acetylation, a solution of acetic anhydride in Tetrahydrofuran or acetonitrile (Capping A) will be mixed in situ during reaction with a catalytic acting solution of N-methylimidazole (Capping B). Additives such as pyridine and lutidine function as mild bases to enhance the efficiency of the capping reaction.

Product of emp Biotech GmbH

Size bottle:

450 mL, 28-400 thread, emp Biotech part no. NC-0701-M450.0-001

2.5 L with GL 45 thread, emp Biotech part no. NC-0701-N002.5-001