title: Uniformity of ionization response of structurally diverse analytes using a chip-based nanoelectrospray ionization source.
abstract: The major drawback of liquid chromatography/mass spectrometry (LC/MS) for the analysis of mixtures is the non-quantitative nature of these studies. The ionization efficiency of the various components in the mixture (e.g., a compound and its metabolites) can vary greatly and, therefore, relative intensities of signals cannot be related to relative abundance. A chip-based nanoelectrospray ionization source was used to compare the ionization efficiencies of compounds with different physical-chemical characteristics. The data indicate that the ionization efficiencies vary much less with the chip-based device than by LC/MS. This was ascribed to the generation of a much higher electric field around the nozzles, which supplies a large excess of protons to the small droplets and reduces/eliminates the differences in the ionization efficiency for the analytes.
authors.affiliation: Pfizer Global Research and Development, Department of Pharmacokinetics, Dynamics and Metabolism, Eastern Point Road, Groton, CT 06340, USA. cornelis.e.hop@pfizer.com
authors.forename: Cornelis E C A
authors.initials: CE
authors.lastname: Hop
authors.forename: Yue
authors.initials: Y
authors.lastname: Chen
authors.forename: Li J
authors.initials: LJ
authors.lastname: Yu
mesh_terms: D000818:Animals; D014150:Antipsychotic Agents / Q000032:analysis / Q000737:chemistry; D005978:Glutathione / Q000032:analysis / Q000737:chemistry; D006801:Humans; D046208:Microchip Analytical Procedures; D036103:Nanotechnology / Q000379:methods*; D004364:Pharmaceutical Preparations / Q000737:chemistry / Q000378:metabolism*; D010879:Piperazines / Q000032:analysis / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods*; D013844:Thiazoles / Q000032:analysis / Q000737:chemistry
chemical_list: D014150:Antipsychotic Agents; D004364:Pharmaceutical Preparations; D010879:Piperazines; D013844:Thiazoles; C092292:ziprasidone; D005978:Glutathione