Related Experiment Video
Updated: Jun 1, 2026

Highly Sensitive and Quantitative Detection of Proteins and Their Isoforms by Capillary Isoelectric Focusing Method
Published on: September 19, 2018
High-resolution capillary isoelectric focusing-electrospray ionization mass spectrometry for hemoglobin variants
1Department of Chemistry and Ames Laboratory [Formula: see text] USDOE, Iowa State University, Ames, Iowa 50011.
Abstract:
On-line capillary isoelectric focusing (CIEF)-electrospray ionization mass spectrometry (ESIMS) as a two-dimensional separation system is employed for high-resolution analysis of hemoglobin variants A, C, S, and F. The effects of moving ionic boundary inside the CIEF capillary and MS scan rate on the separation resolution and mass detection of hemoglobin variants are investigated. The formation of a moving ionic boundary due to the replacement of background electrolyte counterions with sheath liquid counterions can be minimized by combining cathodic mobilization with a gravity-induced hydrodynamic flow. Hemoglobin variants F and A, with a pI difference of 0.05 pH unit, are almost baseline resolved and identified in CIEF-ESIMS. The concentration detection limit for each hemoglobin variant is in the range of 10(-)(8) M, comparable to that obtained in two-dimensional gel electrophoresis using silver staining. Initial preconcentration during the focusing step and the use of single-ion monitoring scan mode are responsible for improving detection limits.
More Related Videos
05:45Capillary Electrophoresis-based Hydrogen/Deuterium Exchange for Conformational Characterization of Proteins with Top-down Mass Spectrometry
Published on: June 8, 2021
07:46Sheathless Capillary Electrophoresis–Mass Spectrometry for Metabolic Profiling of Biological Samples
Published on: October 1, 2016
Related Concept Videos
Capillary Electrophoresis: Applications
Capillary zone electrophoresis (CZE) separates ionic components based on their electrophoretic mobility. It has been used to separate proteins, amino acids,...
Electrophoresis: Overview
There...
Capillary Electrophoresis: Instrumentation
Mass Spectrometry: Complex Analysis
GC–MS is a powerful hyphenated method commonly used in forensics and environmental...
High-Resolution Mass Spectrometry (HRMS)
Electrospray Ionization (ESI) Mass Spectrometry
ESI utilizes electrical energy to transfer ions from the liquid phase of the sample into the...