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On‐line concentration of neutral and charged species in capillary electrochromatography with a methacrylate‐based monolithic stationary phase
Author(s) -
Ping Guichen,
Zhang Yukui,
Zhang Weibing,
Zhang Lin,
Zhang Lihua,
SchmittKopplin Philippe,
Kettrup Antonius
Publication year - 2004
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200305693
Subject(s) - capillary electrochromatography , electrochromatography , materials science , monolithic hplc column , capillary action , chromatography , analytical chemistry (journal) , sensitivity (control systems) , stacking , frit , fabrication , methacrylate , benzoin , polymer , chemistry , composite material , polymerization , organic chemistry , electronic engineering , polymer chemistry , engineering , medicine , alternative medicine , pathology
A method involving self‐concentration, on‐column enrichment and field‐amplified sample stacking for on‐line concentration in capillary electrochromatography with a polymer monolithic column is presented. Since monolithic columns eliminate the frit fabrication and the problems associated with frits, the experimental conditions could be more flexibly adjusted to obtain higher concentration factor in comparison with conventional particulate packed columns. With self‐concentration effect, the detection sensitivity of benzene and hexylbenzene is improved by a factor of 4 and 8, respectively. With on‐column enrichment and ultralong injection, improvement as high as 22 000 times in detection sensitivity of benzoin is achieved. Furthermore, a combination of the three above‐mentioned methods yields up to a 24 000‐fold improvement in detection sensitivity for caffeine, a charged compound. Parameters affecting the efficiency of on‐line concentration are investigated systematically. In addition, equations describing on‐line concentration process are deduced.