Coupling: This support should be used in a manner identical to normal protected nucleoside support since it contains the DMT group.
Deprotection: Use ammonium hydroxide and deprotect as required by nucleobases. When using AMA, a small amount of a non-fluorescent impurity will be formed. To eliminate this impurity, first deprotect with ammonium hydroxide for 30 minutes at room temperature, add an equal volume of 40% methylamine and then complete the deprotection as required by the nucleobases - e.g. 10 minutes at 65°C or 2 hours at room temperature for standard bases.
QUESTION: Does AMA or methylamine cause any degradation to fluorescein or fluorescein-type dyes such as FAM or FITC?
RESPONSE:Response: While AMA (Ammonium hydroxide/40% Methylamine 1:1 v/v) is considered compatible with fluorescein, the use of methylamine when deprotecting a Fluorescein-labeled oligo does lead to a small amount of degradation, which is characterized by a the appearance of a late-eluting peak by RP HPLC that shows no visible fluorescein absorbance. With standard deprotection conditions (AMA 10 minutes at 65 C) the amount of degradation is approximately 5%