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Purification Options

Standard purification
Standard purified oligos are deprotected and desalted, recommended for high through-put methods like PCR, (cycle) sequencing and hybridisation without any restrictions.

OPC purification (Oligonucleotide Purification Cartridge™)
OPC purification is a kind of fast HPLC purification for unmodified oligos up to about 40 nucleotides in length. Non-DMT bearing failure sequences, by-products, and other impurities wash through the cartridge while the DMT group of the trityl-on oligos adsorb to the affinity column. After removal of the DMT group with mild acid the highly purified detritylated primer can be eluted.

HPLC purification
HPLC purification by a computer controlled HPLC-system is the state of the art method to precisely enrich for long full-length products. Its sensitive separation capability makes it possible to get purities up to 95%. Our special developed HPLC programs aren't "2-minute one cleans all kind of oligos programs" as you'll find it by many of our competitors. We have different programs for different types of oligos which have a run time up to 30 minutes. As a documentation of your oligos quality you'll get the HPLC chromatogram with your primers.
We strongly recommend HPLC purification for all modified oligos!

Very long oligonucleotides
From our experience in nucleotide synthesis chemistry you should avoid to design oligo-/polynucleotides longer than 80 bases for high precise applications. Even if we can do up to 180-mers, the yield of full-length product will (coupling rates/cycle ~ 98.5-99.5%) dramatically decrease with the number of synthesis cycles and (de) protection, coupling and washing steps within each cycle can leave its track within the growing sequence (base modifications by oxidation, base insertions/deletions by formation of secondary structures, ...). Consequently, a precise sequence guarantee is very difficult to give and we have to double the price per base for oligos >80 nucleotides.

Quality Control and Documentation

Quality control is the last step in the production process of custom oligonucleotides. Our Quality Management starts before the first step!

  • Pre-synthesis control: Validation of incoming raw material/chemicals by running and checking test oligos makes sure that our reagents, which are exclusively purchased from audited and approved quality vendors, meet the requirements for providing best coupling efficiencies and consequently top quality primers.
  • In-synthesis control: During synthesis coupling rates are permanently checked by DMT monitoring - only high efficient (>98.5 %) cycles allow the continuation of the synthesis run!
  • Post-synthesis control: Quantification (OD measurement) of the end product is a strong indicator for successful synthesis.
  • End control: Analytical HPLC and Maldi-ToF spot checks are performed for final release of the product.
Our strict maintenance program for regular testing of the performance of our synthesizers is an additional "quality measure" taken from our side to guarantee our constantly high quality level.

Deprotection of Thiol-modified Oligonucleotides - short protocol

Just prior to use, cleave the disulfide with 100 mM DTT (pH 8.3-8.5) at RT for about 30 minutes. Thiol-modified deprotected oligonucleotides should be kept either under an inert atmosphere or in a solution containing DTT (10 mM) to avoid disulfide formation.