title: Improved sensitivity by post-column chemical environment modification of CE-ESI-MS using a flow-through microvial interface.
abstract: Post-column chemical environment modification can affect detection sensitivity and signal appearance when capillary electrophoresis is coupled through electrospray ionization to mass spectrometry (CE-ESI-MS). In this study, changes in the signal intensity and peak shape of N-Acetylneuraminic acid (Neu5Ac) were examined when the modifier solution used in a flow-through microvial interface for CE-ESI-MS was prepared using an acidic or basic background electrolyte (BGE) composition. The use of a basic modifier resulted in improved detection compared to the results obtained when an acidic modifier was used in negative ion mode. Increased sensitivity and more symmetrical peak shape were obtained. Using an acidic modifier, the LOD of Neu5Ac was 47.7 nM, whereas for a basic modifier, the LOD of Neu5Ac was 5.20 nM. The calculated asymmetry factor at 100 nM of Neu5Ac ranged from 0.71 to 1.5 when an acidic modifier was used, while the factor ranged from 1.0 to 1.1 when a basic modifier was used. Properly chosen post-column chemical modification can have a significant effect on the performance of the CE-MS system.
authors.affiliation: Department of Chemistry, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Jessica May
authors.initials: JM
authors.lastname: Risley
authors.affiliation: Department of Chemistry, University of British Columbia, Vancouver, BC, Canada.
authors.forename: David Da Yong
authors.initials: DDY
authors.lastname: Chen
mesh_terms: D004573:Electrolytes; D019075:Electrophoresis, Capillary / Q000379:methods*; D007785:Lactose / Q000031:analogs & derivatives / Q000737:chemistry / Q000302:isolation & purification; D019158:N-Acetylneuraminic Acid / Q000737:chemistry / Q000302:isolation & purification*; D009438:Neuraminic Acids / Q000737:chemistry / Q000302:isolation & purification; D009844:Oligosaccharides / Q000737:chemistry / Q000302:isolation & purification; D012680:Sensitivity and Specificity; D012794:Sialic Acids / Q000737:chemistry / Q000302:isolation & purification; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: C421467:3'-sialyllactose; D004573:Electrolytes; D009438:Neuraminic Acids; D009844:Oligosaccharides; D012794:Sialic Acids; C032592:N-glycolylneuraminic acid; C000020:N-acetylneuraminoyllactose; D019158:N-Acetylneuraminic Acid; D007785:Lactose
keywords: Capillary electrophoresis; Electrospray ionization; Mass spectrometry; Peak symmetry; Post-column modification; Sensitivity