We offer two types of randomization.
We let the machine do it (send all four monomers to the column at one time). Because of the relative binding efficiencies of the different amidites, and the fact that all four amidites may not hit the column at precisely the same instant, this may result in a mixture of oligo s where T:G:C:A is not exactly 25:25:25:25. Each random base is charged at the normal per base price. This is the most economical way to randomize the oligo if your reaction will not be affected by slightly skewed coupling.
To help improve true randomization, we will hand mix a bottle of reagents and put that on a fifth port on the synthesizer. This will ensure a 1:1:1:1 ratio for your oligo. Specialized ratios are also available with this service. Please see our Custom Preparative Services Catalog Page for pricing information. Currently our insertion limits are:
- 100 mixed sites (of the same mix) on the 100 or 250nmol scale per mix.
- 40 mixed sites (of the same mix) on the 1uMol scale per mix.
- 10 mixed sites (of the same mix) on the 5umol or 10umole scale per mix
If you would like to order handmixed bases on the web, please use the Mixed Bases tab on the Order Oligos page