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.

Prepacked in two bottle sizes:

450 mL in a 28-400 thread glass bottle, emp Biotech part no. NC-0801-M450.0-001

2.5L in a GL45 thread glass bottle, emp Biotech part no. NC-0801-N002.5-001

Product of emp Biotech