title: Some possibilities of an analysis of complex samples by a mass spectrometry with a sample pretreatment by an offline coupled preparative capillary isotachophoresis.
abstract: This work deals with an analysis of biologically important compounds in complex matrices using preparative isotachophoresis (pITP) in column coupling configuration as a sample pretreatment technique followed by a direct infusion mass spectrometry with nano-electrospray ionization (DI-nESI-MS). Busereline was chosen as a model analyte, and urine was chosen as an example of complex matrix. In pITP experiments, sodium cation (10 mmol/L concentration) was used as a leading ion and β-alanine as terminating ion (20 mmol/L concentration). The fractions, obtained by pITP pre-separation with the assistance of the mixture of discrete spacers, were finally analyzed by DI-nESI-MS. It was shown that pITP performed before DI-nESI-MS analysis can significantly simplify complex matrix, and, due to its concentration power, pITP can consequently decrease the concentration limit of detection. The concentration of buserelin in the urine samples analyzed by pITP-DI-nESI-MS was 10 μg/L (reflecting at a 8.10⁻⁹  mol/L concentration) in our work but from the ion intensities obtained in MS as well as MS/MS analyses, it is clear that this concentration level could be several orders of magnitude lower for reliable detection and identification of buserelin in urine analyzed using pITP with DI-nESI-MS detection.
authors.affiliation: Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovak Republic. marak@fns.uniba.sk
authors.forename: Jozef
authors.initials: J
authors.lastname: Marák
authors.forename: Andrea
authors.initials: A
authors.lastname: Staňová
authors.forename: Soňa
authors.initials: S
authors.lastname: Gajdoštínová
authors.forename: L'udovít
authors.initials: L
authors.lastname: Skultéty
authors.forename: Dušan
authors.initials: D
authors.lastname: Kaniansky
mesh_terms: D001826:Body Fluids / Q000737:chemistry*; D002064:Buserelin / Q000652:urine; D019075:Electrophoresis, Capillary / Q000379:methods*; D057625:Isotachophoresis / Q000379:methods*; D004364:Pharmaceutical Preparations / Q000032:analysis; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry
chemical_list: D004364:Pharmaceutical Preparations; D002064:Buserelin