Separation and characterization of NISTmAb charge variants with CEInfinite on-line iCIEF-MS

On-line iCIEF-MS coupling using the CEInfinite Preparative iCIEF instrument system was verified by the congruent charge isomer peaks between the iCIEF separation of the NISTmAb and its input into the MS, as well as the successful identification of the individual peaks. This technique can easily be applied to other mAbs as well as other protein-based biopharmaceuticals with little additional development from the initial iCIEF method.