How Pure is Pure Enough?
In general, the purity level that you require depends on the effect that failed sequences (n-1, n-2,... Oligomers) will have on your experiments.
For some applications, desalted Oligos are satisfactory. For others, only PAGE purification can yield Oligos of sufficient purity. We recommend the use of purified Oligos for high risk projects (for example cloning of Oligos longer than 50mer) or Oligos which are routinely used for diagnostic purposes.
Please note that yields vary according to the selected purification method.
Desalted Oligos
All Oligos are at least desalted to remove residual by-products from the synthesis, cleavage and deprotection procedures.
Such purification is sufficient for Oligos shorter than 35 and/or Oligos used for non critical applications like PCR, sequencing, probing, mobility shift, or hybridization. They are not recommended for more sophisticated projects like cloning.
HPLC Purified Oligos
Oligos 50 bases or shorter can be HPLC purified using a Reverse Phase HPLC system. Residual, truncated DMT-off Oligo molecules from synthesis are therefore removed during the purification process, resulting in a purity > 85%.
HPLC purified Oligos are recommended for applications such as DNA fingerprinting, RT-PCR, in situ hybridization, microsatellite polymorphisms and mutagenesis. Of course, you can always use HPLC purified Oligos for other applications as well.
PAGE Purified Oligos
Oligos 51 bases or longer should be PAGE purified. With the excellent resolution resulting from PAGE, 95-99% purity can be achieved. In many cases, full length Oligos can be separated from Oligos which are just one base shorter. This purification grade is recommended for all applications including gene synthesis, primer extension, 32P-labeling and cloning of Oligos longer than 50mer.
NMR Grade Oligos (HPLC & Dialysis Purified Oligos)
If you would like to use antisense Oligos in cell culture, it is important to remove salts within the Oligo sample. Our NMR grade Oligos are the perfect choice to avoid problems with salts in your antisense experiments.
Our NMR grade Oligos are precipitated and carefully dialysed after a Reverse Phase HPLC purification.
This method is mainly used for phosphorothioates (PTO), large scale synthesis and NMR grade Oligos. This purification grade is available for any Oligo longer than 7 bases.
