Cation exchange chromatography is practiced with either a strong or a weak cation exchange column, containing a sulfonium ion, or with a weak cation exchanger, having usually a carboxymethyl (CM) functional group. A counter ion, often Na+ maintains electroneutrality. In ion exchange chromatography the pH of the mobile phase buffer must be between the pI or pKa of the charged molecule and the pKa of the charged groups on the solid support. For example, a molecule with a pI of 8.2 is run in a mobile phase buffer at pH 6.0 with the solid support pKa at 1.2 in cation exchange chromatography. Specialty columns: Organic acids by ion-exclusion (TSKgel OApak-A and TSKgel SCX)

Highlights Pore structure and bonding chemistry of TSKgel BioAssist S provides high capacity for medium to large molecular weight proteins. TSKgel BioAssist columns are packed in 4.6mmID or 10mmID PEEK hardware.  Other columns are available in glass and stainless steel for anlytical, semi-preparative and preparative applications. Binding capacity  for small to medium size proteins on TSKgel DEAE-3SW is approximately double that of the 5PW packings due to the smaller pore size and larger surface area. TSKgel SP-5PW column available in 2mmID format. Very efficient chromatography can be achieved with the TSKgel STAT columns due to the novel bonding chemistry and the absence of micro-pores.

Strong Cation Exchange	Weak Cation Exchange
Polymethacrylate: TSKgel BioAssist S TSKgel SP-5PW TSKgel SP-NPR Silica: TSKgel SP-2SW Polystyrene: TSKgel SCX Polymer: TSKgel SP-STAT Polymethacrylate: TSKgel CM-5PW TSKgel OApak-A Silica: TSKgel CM-2SW TSKgel CM-3SW Polymer: TSKgel CM-STAT