It is common when carrying out phosphoramidite chemistry for users to maximise coupling efficiency through drying of the amidite solutions with molecular sieves. This is particularly true in RNA synthesis and indeed we would recommend this approach in using our TC chemistry. Our preparation method for molecular sieves is shown below.
To prepare the sieves (4Å or 3Å):
Pour them into a buchner funnel with no filter paper (but make sure the holes are small enough that the sieves don't fall into them).
Wash them with:
- 1% oxalic acid in DCM (don't use deblock)
- 2% DIPEA (or TEA) in MeCN
Dry in an oven at 150-200oC over the weekend.
Store in a vacuum dessicator.
Please note that we do not sell molecular sieves. These are widely available from general chemical vendors.