Purification & Yield

The standard salt-free purification is the default purity option for our oligos. For oligos shorter than 40 bases, salt-free purity is appropriate in many applications including routine PCR, DNA sequencing, microarray fabrication, and blotting.

*Guaranteed yield is for unmodified oligos, 15–50 bases. Yield will vary with oligo composition, length, and purification. Minimum yields do not apply to express products.

*Guaranteed yield is for unmodified oligos, 15–50 bases. Yield will vary with oligo composition, length, and purification.

*Expected yield for a PAGE oligo that includes one modification would be ~60% of the value listed.

There is commonly confusion between the synthesis scale and yield. In short, the scale is the amount of starting material and yield is the amount of ending material.

In the realm of chemistry, perfection remains an elusive dream and Eurofins Genomics comes as close as any vendor to achieving this dream but inevitably this means there will always be material lost in the process. The synthesis process involves several stages: the coupling of individual bases, separating the oligo from its solid support, desalting, normalization, and additional purification on request. Each step inevitably incurs a toll on the final yield, a toll that varies based on the parameters of the order. In light of this inherent variability, many oligo companies structure pricing and other options based on the starting scale. In addition, Eurofins Genomics provides a minimum yield tailored to the oligo's sequence, starting scale, and the customary yield observed under predefined conditions to provide customers a level of predictability and reliability.

To determine the appropriate scale to order, consider these factors:

1. What is minimum purity level required for the technique(s) to be used?
2. How much material is needed to complete the full investigation?
3. Consult the yield tables to match the quantity of oligo required (listed by purification method) to the appropriate synthesis scale.

Although DNA synthesis often results in more material than the guaranteed minimum, if completing your experiments will require more than the minimum material then we highly recommend ordering a larger synthesis scale. For extended studies, we recommend that you freeze (–20 ^oC) aliquots the oligo, thawing a fresh aliquot for each stage of your investigations.

What is Scale?

So, what exactly is synthesis scale? Scale is the quantity of initial materials employed in the synthesis.

Oligonucleotide synthesis typically occurs within columns featuring a solid support amidst filters. Within these columns, the 3'‑most nucleotide of the custom oligo sequence is affixed to the solid supports. Subsequently, the oligo synthesis proceeds from the 3’ to the 5’ end through the utilization of nucleoside phosphoramidite monomers. 

Numerous factors influence the the amount of material that is synthesized using this method. For instance, coupling efficiency is a important factor. It denotes the pace at which the subsequent phosphoramidite monomer reacts with the free 5’-OH of the solid-support-linked nucleoside. Other important factors include purification and deprotection.

What is Yield?

Now, onto synthesis yield – the fruit of labor, the culmination of all synthesis and purification processes entwined with the oligonucleotide.

The final yield, post-reaction and purification, never mirrors the initial quantity (scale) with 100% efficiency. Modifications, secondary structures, and purification impact the ultimate quantity (yield) delivered. However, Eurofins Genomics provides guaranteed yields based on the synthesis scale, modifications, length, and purification.

These are general guidelines for common applications, but customers are free to choose for themselves the appropriate purification. Available purification options are determined by oligo length, modifications, and synthesis scale.