Multidimensional microchip-capillary electrophoresis device for determination of functional proteins in infant milk formula

Abstract

Functional proteins have been found in infant milk formula as supplements, added by an increasing number of manufacturers. Their supplementations are expected to be controlled and monitored. Here, we describe a microchip-integrated CE method for the determination of these low levels of functional proteins in a proteinrich sample matrix. On-chip isoelectric focusing (IEF) is used to separate high- abundance proteins from low-abundance proteins instead of using some complicated time-consuming protein purification process. After that, transient isotachophoresis hyphenated capillary zone electrophoresis (t-ITP- CZE) can preconcentrate, separate, and analyze transferred functional proteins in the embedded capillary under UV detection.