icIEF-UV/MS analysis with the Intabio ZT cartridge enables separation of charge variants by imaged capillary isoelectric focusing, UV quantitation and electrospray ionization (ESI) directly into a mass spectrometer for further mass analysis and peak identification, all with the use of MS-compatible reagents.

2025年3月1日 · This integrated protocol unifies two key workflows—fractionation and MS online analysis—on a unique icIEF system, enabling in-depth characterization of protein peaks observed in icIEF-UV analysis.

The icIEF-UV provides reproducible high-resolution separation of the main peak (M) and its charge variants (A: acidic, B: basic, middle figure). The MS capability of the icIEF-UV/MS enables confident assignment of proteoforms detected under each variant peak.

全柱成像毛细管等电聚焦（imaged capillary isoelectric focusing, iCIEF）是一种基于蛋白质等电点（isoelectric point, pI）将其分离的技术，在生物制药行业中被广泛应用于电荷变异体的分析。

This innovative system offers direct chip-based integration of imaged capillary isoelectric focusing (icIEF) with mass spectrometry (MS), which affords confident characterization of proteins and reliable quantitation of charge variants by icIEF-UV/MS. Further, the streamlined icIEF-UV/MS platform significantly reduces the time to results from ...

2011年11月1日 · iCIEF separation is conducted by focusing isoforms in an ampholytic pH gradient through an applied electric field. Following the focusing step is a detection step, which in conventional CIEF would entail a chemical or pressure mobilization across a fixed UV detector 4,.

2022年5月1日 · Recent advancements have significantly enhanced the sensitivity by UV-induced native fluorescence and immunoassay-coupled chemiluminescence detection of icIEF, and the coupling of icIEF to MS for peak identification and characterization further expands the ability of icIEF to serve as a multi-attribute method.

2023年3月29日 · 近期，在Analytical Methods上发表的一篇文章，介绍了基于成像毛细管等电聚焦（iCIEF）的馏分收集和在线质谱联用的分析平台来表征抗体电荷异质性。 抗体的电荷变异体经过iCIEF分离后：1）通过MS直接检测分子量；2）通过组分收集的方式获取异构体的纯组分，并用HPLC-MS分析其完整分子量。 研究发现，由于iCIEF-MS的检测灵敏度高于HPLC-MS，因此能在mAb的电荷变异体分析中，iCIEF-MS能观察到HPLC-MS无法检测到的一些低丰度的糖型。 这 …

icIEF-UV/MS Peak Characterization Discussion and Summary • Both INT-01 and ADC-1 were separated under IntaBio ZT platform icIEF-UV/MS conditions. Conjugation of INT-01 into ADC-1 resulted in both a reduction in pI and increase in charge heterogeneity

Why is Peak Identification Needed for icIEF? Pfizer has a portfolio of divergent and complex modalities For AAV, capsid deamidation is a CQA. An icIEF method was able to be developed; however, it is unclear which peaks represent which capsid proteins and/or acidic species thereof Assigning icIEF peaks was a complex, multiyear process and