title: Metabolite profiling of human urine by CE-ESI-MS using separation electrolytes at low pH.
abstract: We investigated the potential of CE coupled to electrospray MS (CE-ESI-MS) in metabolite profiling of human urine without any sample prefractionation step. A heterogeneous mixture of biologically relevant compounds covering a broad range of physicochemical properties was used to optimize separation conditions in fused-silica capillaries. A running electrolyte containing 50 mM of acetic acid and 50 mM of formic acid at pH 2.5 was used for the CE separations. A sheath-flow electrospray interface was employed for CE-ESI-MS analysis. Sheath liquids containing 80:20 v/v methanol/water with 0.1% v/v of acetic acid or 60:40 v/v isopropanol/water with 0.5% v/v of ammonia were selected for optimum detection in positive and negative ESI modes, respectively. Reproducibility and sensitivity were studied, and strategies for identification of the separated urinary compounds are suggested. We report major advantages and disadvantages of CE-ESI-MS for metabolite profiling of human body fluids. This work may be regarded as a first step in the use of CE-ESI-MS for reliable differential analysis of body fluids from healthy and diseased individuals.
authors.affiliation: Division of Analytical Biosciences, Leiden/Amsterdam Center for Drug Research, Center for Medical Systems Biology, Leiden, The Netherlands.
authors.forename: Fernando
authors.initials: F
authors.lastname: Benavente
authors.forename: Rob
authors.initials: R
authors.lastname: van der Heijden
authors.forename: Ubbo R
authors.initials: UR
authors.lastname: Tjaden
authors.forename: Jan
authors.initials: J
authors.lastname: van der Greef
authors.forename: Thomas
authors.initials: T
authors.lastname: Hankemeier
mesh_terms: D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014466:Ultraviolet Rays; D014556:Urine / Q000737:chemistry*