Our advanced DNA synthesizers and our care with chemical reagents result in high quality oligonucleotides. Desalted DNA is suitable for direct use in sequencing or PCR in many cases. However, we offer a range of DNA purification protocols using tC-18 Sep-Pak^TM cartridge or reversed-phase HPLC. The recovery yield from oligo purification is 25-50% of the synthetic yield. DNA with modifications may give lower yields.

After deprotection, the ammonia solution is removed from the oligonucleotide by vacuum. All the protected groups, small failure strands and ammonia salt are then removed by sodium acetate-ethanol precipitation. The resulting oligo is in sodium salt form. Desalted, quantified and lyophilized DNA, with synthesis report, is delivered in 2 business days.

HPLC Purification

The trityl-on full length DNA strands are separated from the trityl-on and trityl-off failure strands by HPLC on a reversed-phase PRP-1 Hamilton column (4.1 x 250 mm), and the trityl groups are removed on the column with trifluoroacetic acid. The full length oligos are collected, desalted with ethanol precipitation, quantified and lyophilized. HPLC-purified DNA, with HPLC and synthesis report, is delivered in 5 business days.

Cartridge Purification

The trityl-on DNA strands are separated from the trityl-off failure strands on a tC-18 Sep-Pak^TM cartridge. Detritylation is carried out on the cartridge with trifluoroacetic acid. Detrityled oligos are collected, desalted with ethanol precipitation, quantified and lyophilized. Cartridge purification is less effective than HPLC and recommended only for unmodified oligos less than 40 nucleotides in length. Cartridge purified DNA, with synthesis report, is delivered in 3 business days.