0000000000283092
AUTHOR
Robertus Hendriks
Profiling of endogenous peptides by multidimensional liquid chromatography: On-line automated sample cleanup for biomarker discovery in human urine.
A simple and flexible system, employing a column switching technique, has been designed to allow the analysis of peptides and proteins smaller than 15 kDa by molecular weight in filtered urine samples by performing a direct on-column injection utilising simultaneous sample clean-up and trace enrichment. The positively charged peptides and small proteins in the sample are attracted to the inner, negatively charged pore structure of the RAM-SCX column while the larger proteins and uncharged or negatively charged compounds are excluded. After preconditioning with the biological sample, large amounts of sample can be injected. Several important and adjustable parameters for the proper use of a …
Selective protein removal and desalting using microchip CE.
Abstract 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 rem…