title: On-line concentration of proteins in pressurized capillary electrochromatography coupled with electrospray ionization-mass spectrometry.
abstract: Pressurized capillary electrochromatography (pCEC) and electrospray ionization-mass spectrometry (ESI-MS) have been hyphenated for protein analysis. Taken cytochrome c, lysozyme, and insulin as samples, the limits of detection (LODs) for absolute concentrations are 10(-11) mol (signal-to-noise ratio S/N = 3) with relative standard deviations (RSDs) of retention time and peak area, respectively, of less than 1.7% and 4.8%. In order to improve the detection sensitivity, on-line concentration by field-enhanced sample-stacking effect and chromatographic zone-sharpening effect has been developed, and parameters affecting separation and detection, such as pH and electrolyte concentration in the mobile phase, separation voltage, as well as enrichment voltage and time, have been studied systematically. Under the optimized conditions, the LODs of the three proteins could be decreased up to 100-fold. In addition, the feasibility of such techniques has been further demonstrated by the analysis of modified insulins at a concentration of 20 microg/mL.
authors.affiliation: National Chromatography Research & Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Liang
authors.forename: Lihua
authors.initials: L
authors.lastname: Zhang
authors.forename: Jicheng
authors.initials: J
authors.lastname: Duan
authors.forename: Chao
authors.initials: C
authors.lastname: Yan
authors.forename: Weibing
authors.initials: W
authors.lastname: Zhang
authors.forename: Yukui
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D011312:Pressure; D011506:Proteins / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D011506:Proteins