title: Sheathless capillary electrophoresis-mass spectrometry for anionic metabolic profiling.
abstract: The performance of CE coupled on-line to MS via a sheathless porous tip sprayer was evaluated for anionic metabolic profiling. A representative metabolite mixture and biological samples were used for the evaluation of various analytical parameters, such as peak efficiency (plate numbers), migration time and peak area repeatability, and LODs. The BGE, i.e. 10% acetic acid (pH 2.2), previously used for cationic metabolic profiling was now assessed for anionic metabolic profiling by using MS detection in negative ion mode. For test compounds, RSDs for migration times and peak areas were below 2 and 11%, respectively, and plate numbers ranged from 60 000 to 40 0000 demonstrating a high separation efficiency. Critical metabolites with low or no retention on reversed-phase LC could be efficiently separated and selectively analyzed by the sheathless CE-MS method. An injection volume of only circa 20 nL resulted in LODs between 10 and 200 nM (corresponding to an amount of 0.4-4 fmol), which was an at least tenfold improvement as compared to LODs obtained by conventional CE-MS approaches for these analytes. The methodology was applied to anionic metabolic profiling of glioblastoma cell line extracts. Overall, a sheathless CE-MS method has been developed for highly efficient and sensitive anionic metabolic profiling studies, which can also be used for cationic metabolic profiling studies by only switching the MS detection and separation voltage polarity.
authors.affiliation: Leiden Academic Center for Drug Research, Division of Analytical Biosciences, Leiden University, Leiden, The Netherlands.
authors.forename: Mehmet Can
authors.initials: MC
authors.lastname: Gulersonmez
authors.affiliation: Sciex, Phoenix House, Center Park, Warrington, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Lock
authors.affiliation: Leiden Academic Center for Drug Research, Division of Analytical Biosciences, Leiden University, Leiden, The Netherlands.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hankemeier
authors.affiliation: Leiden Academic Center for Drug Research, Division of Analytical Biosciences, Leiden University, Leiden, The Netherlands.
authors.forename: Rawi
authors.initials: R
authors.lastname: Ramautar
mesh_terms: D000838:Anions / Q000032:analysis*; D045744:Cell Line, Tumor; D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D057230:Limit of Detection; D055442:Metabolome / Q000502:physiology; D055432:Metabolomics / Q000379:methods*; D016062:Porosity; D015203:Reproducibility of Results
chemical_list: D000838:Anions
keywords: Anionic metabolites; Glioblastoma cell line; Mass spectrometry; Metabolic profiling; Sheathless porous tip interface