Most proteins have isoelectric points below 7, and are best purified or analyzed by anion-exchange chromatography. PolyWAX LP is a weak anion-exchange (WAX) material developed for chromatography of enzymes and other proteins. Selectivity is excellent, with high or quantitative recovery of applied activity. PolyWAX LP can be used in the mixed mode in the Hydrophilic -Anion exchange mode by adding some organic solvents in the mobile phase. This technique has been used for some membrane proteins.
Most Anion-exchange materials based on polyethyleneimine (PEI) are prepared with the conventional branched polymer. PolyWAX LP is prepared with linear PEI, which confers greater selectivity and recovery. PolyWAX LP is also used for anion-exchange of acidic small molecules such as a red dye #2 and #40, benzoate and sorbate in fruit juice.