Cap A

Cap A solution contains acetic anhydrideanhydride, lutidine and tetrahydrofuran (THF). It is used after the phosphoramidite reaction/coupling step. The solution is configured for ABI.

Cap A solution aborts chains bearing unreacted 5′ hydroxyl groups due to failure of reaction with activated phosphoramidite (typically, 1 to 2% of growing oligonucleotide chains in each synthesis cycle). These unreacted 5′ hydroxyl groups are capped with an acetyl group and thus rendered unreactive for subsequent synthesis steps.

四氢呋喃/二甲基吡啶/乙酸酐 8/1/1 (v/v/v)