Switching valve with internal micro precolumn for on-line sample enrichment in capillary zone electrophoresis

Combining solid-phase preconcentration, capillary electrophoresis and off-line matrix-assisted laser desorption/ionization mass spectrometry: intracerebral metabolic processing of peptide Ein vivo

“…15 An enrichment capacity of at least two orders of magnitude has been demonstrated in spPCÈCE for a variety of analyte types,17h22 although a compromised performance of CE has been observed. 15,23 In addition, the relatively large volumes of organic solvent required to elute analytes from the solid phase within the capillary may also have an adverse e †ect on the CE process.15,23 Another approach is the use of an on-line impregnated membrane preconcentrator (mPCÈCE) in conjunction with tITP for the CE analysis of peptides. 24 In this paper, we describe an in vivo study of peptide E metabolism which utilizes a capillary solid-phase preconcentration apparatus in an "on-line transfer, o †-line analysisÏ approach to achieve optimum performance in CE and subsequent matrix-assisted laser desorption/ ionization mass spectrometric (MALDI/MS) analysis.…”

Design and applications of coupled SPE‐CE

“…Phthalates were concentrated and separated using such a setup. Debets et al [149] used a similar approach in which the SPE column was positioned inside the valve. However, the design caused excessive peak broadening if the SPE column was continuously inline with the CE system during analysis.…”

“…Special online SPE-CE systems have been developed, in which the SPE column is part of an interface that is positioned in the CE system [149][150][151][152][153][154]. One approach uses a fourport two-way microvalve with an internal Zylon fiber-in-tube SPE column that is inline coupled to a CEC system [150,151].…”

An Improvement of the On-line Electrophoretic Concentration Method for Capillary Electrophoresis of Proteins and Experimental Factors Affecting the Concentration Effect

“…3 On-line sample concentration is known to be an effective approach for improvement of the concentration sensitivity of CE. [4][5][6][7][8][9][10][11][12][13][14][15] Recently, we have reported a novel on-line electrophoretic concentration method for CE of proteins. 16 In our proposed method, a short semipermeable hollow fiber is connected to the inlet end of a capillary.…”