Selective protein removal and desalting using microchip CE

• Published in: Journal of chromatography. B 2006-07, Vol.839 (1), p.68-73
• Main Authors: Silvertand, L.H.H., Machtejevas, E., Hendriks, R., Unger, K.K., van Bennekom, W.P., de Jong, G.J.
• Format: Article
• Language: English
• Subjects: 2D microfluidic device; Analysis; Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Electrophoresis, Microchip - instrumentation; Electrophoresis, Microchip - methods; Fundamental and applied biological sciences. Psychology; General pharmacology; Humans; Isotachophoresis-zone electrophoresis; Medical sciences; On chip sample pretreatment; Online Systems; Pharmacology. Drug treatments; Proteins - chemistry; Proteins - isolation & purification; Proteins and peptides; Sample depletion
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/j.jchromb.2006.03.036

This paper describes the on-line sample pretreatment and analysis of proteins and peptides with a poly(methylmethacrylate) (PMMA) microfluidic device (IonChip™). This chip consists of two hyphenated electrophoresis channels with integrated conductivity detectors. The first channel can be used for sample preconcentration and sample clean-up, while in the second channel the selected compounds are separated. Isotachophoresis (ITP) combined with zone electrophoresis (CZE) was used to preconcentrate a myoglobin sample by a factor of about 65 before injection into the second dimension and to desalt a mixture of six proteins with 100 mM NaCl. However, ITP–CZE could not be used for the removal of two proteins from a protein/peptide sample since the protein zone in the ITP step was too small to remove certain compounds. Therefore, we used CZE–CZE for the removal of proteins from a protein/peptide mixture, thereby injecting only the peptides into the second CZE separation channel.