Whole column imaging detection capillary isoelectric focusing (iCIEF) has been shown to have many advantages for high resolution protein charged based separation. The charge variants of a protein may associate with pathways of protein degradation. Characterization of the exact change of these variants provides very useful information for stability studies, formulation and processing control. It is desirable to utilize advanced iCIEF technology for preparative protein application.
Nevertheless, there was no commercial solution until AES introduced a breakthrough innovation recently.
AES developed a proprietary column diameter transformation cartridge (patent pending), which has a large inner diameter (ID) separation capillary, and a small ID transfer capillary. Once the proteins are separated, they are forced into the transfer capillary with minimal peak remixing.
The effectiveness of this proprietary cartridge is illustrated with iCIEF separation, individual peak collection, and iCIEF of the collections. The individual peaks were collected at 2 minute intervals, and the fraction was mixed with a carrier ampholytes solution. The iCIEF results of the individual fractions show the efficiency of a 2 minute collection. Mingling of neighboring peaks can be minimized with shorter collection intervals.