1. What types of compounds are isolated using ion exchange?
Proteins, peptides, DNA and RNA derived oligonucleotides and other nucleic acid fragments.
2. What ion exchange chemistries are offered by Tosoh Bioscience?
Polymer-based columns: Weak and strong anion and cation exchangers are available. These columns are designed with 100 nanometer (nm) pore size and various column sizes ranging from analytical to semi-preparative scale. Also available are BioAssist Q (a polyamine anion exchanger) and BioAssist S (a sulfopropyl cation exchanger), both are very large pore size, high capacity, ion exchangers.
Silica-based columns: Weak and strong anion and cation exchangers are available. These columns are designed with 12.5 nm (upper molecular weight limit of 10 kDa) and 25 nm (upper molecular weight limit 30 kDa) pore sizes.
Specialty columns: Cation and anion exchange ligands are attached to a polystyrene-divinylbenzene (PS-DVB) polymeric support. These are used for separation of carbohydrates, amino acids and organic acids.
3. What is the TSKgel DNA-NPR column? How is it different from TSKgel DEAE-NPR?
The dimensions of the TSKgel DNA-NPR column have been optimized for the separation of PCR and other DNA fragments. Due to its small particle size and non-porous resin surface (hence NPR) this column excells at rapid separation of large biomolecules such as DNA digests. TSKgel DEAE-NPR is based on the same chemistry as TSKgel DNA-NPR except for a shorter column length.
4. How do I select an ion exchange resin?
After identifying the isoelectric point of the compound of interest, select a mobile phase pH between the pI and the pKa of the ligand group. Elute the mixture from the column using a salt gradient, e.g. 0.3 mol/L NaCL to 1.0 mol/L NaCL.