What size Oasis HLB and Sep-Pak C18 cartidges can be used to desalt a 1.0 µmol synthesis of DMT-on and DMT-off, 20 mer to 30 mer, single-stranded oligonucleotide? - WKB108913

ENVIRONMENT

• Hydrophilic-lipophilic balance (HLB)
• Polymeric sorbent
• Solid-phase extraction (SPE)
• Sample preparation
• Sep-Pak
• Silica-based packing
• Oligonucletides
• Desalting

ANSWER

DMT-off
186000115 - Oasis HLB 6 cc Vac Cartridge, 500 mg Sorbent per Cartridge, 60 µm, 30/pk

DMT-on:
WAT106202 - Oasis HLB 6 cc Vac Cartridge, 200 mg Sorbent per Cartridge, 30 µm, 30/pk
WAT043365 - Sep-Pak tC18 20 cc Vac Cartridge, 5 g Sorbent per Cartridge, 37 - 55 µm, 20/pk

ADDITIONAL INFORMATION

Small-scale examples:

Desalting of DNA Oligonucleotides by SPE for MALDI Analysis [Excerpt from Oasis Applications Notebook]  

• 1.0 pmol to 5,000 pmol DMT-off oligos can be cleaned up on an Oasis HLB 96-well µElution plate with 2 mg of sorbent in each well.
• Scaled up, this means that about 500 mg of Oasis HLB can be used to clean up a 1.0 µmol synthesis of DMT-off oligos.
• Waters has not evaluated Sep-Pak C18 for cleanup of DMT-off oligos.

DMT On Purification of DNA Oligonucleotides <35mer Using Oasis HLB SPE Products [Excerpt from Oasis Applications Notebook]

• 0.1 to 1.0 µmol of DMT-on oligos can be cleaned up on Oasis HLB 6 cc/200 mg cartridges. 
• ~0.5 nmol of DMT-on oligos can be cleaned up on ~2 mg of Sep-Pak C18. 
• Scaled up, this correlates to about 5 g of Sep-Pak C18 to clean up a 1.0 µmol synthesis of DMT-on oligos.

Loading capacity/breakthrough studies would need to be performed in order to verify the correct loading capacities for each specific oligonucleotide application.

These are guidelines to help determine a starting point with SPE cleanup of oligos.