The need for oligo purification is dependent on a number of factors, including your application and oligo complexity. HPLC and PAGE are the most common purification methods. Reverse phase HPLC (RP-HPLC) is by far the most common, and is very useful in separating dye-labeled from unlabeled oligos, and in separating full-length oligos from truncated species (n-1, n-2, etc.). A crude/desalted preparation of a primer is usually sufficient for a PCR application. Long oligos (45+ bp) do not resolve well by HPLC, therefore PAGE purification is recommended. RNA requires purification under sterile conditions and sterility is most easily controlled during a PAGE purification procedure. Our technical support team can assist you in determining the best purification method for your construct and requirements.