title: Development and characterization of a novel semiautomated arrangement for electrochemically assisted injection in combination with capillary electrophoresis time-of-flight mass spectrometry.
abstract: Electrochemically assisted injection (EAI) is an attractive injection concept for CE that enables the separation of neutral analytes via electrochemical generation of charged species during the injection process. A new semiautomated EAI configuration was developed and applied in conjunction with CE-MS (EAI-CE-MS). The EAI cell arrangement consists of an integrated buffer reservoir for CE separations and a compartment holding screen-printed electrodes. A drop of sample solution (50 μL) was sufficient to cover the three-electrode structures. A piezo motor provided a fast and precise capillary positioning over the screen-printed electrode assembly. Using ferrocene methanol as a model system, the EAI arrangement was characterized regarding coulometric efficiency, precision, and sensitivity of electrospray ionization-time-of-flight-MS. The formation of the cationic oxidation product of ferrocene methanol enhanced the sensitivity of CE-MS determination by two orders of magnitude and the electrochemically formed product showed a migration time corresponding to its individual electrophoretic mobility. Preliminary studies of EAI-CE-MS in the field of the analysis of nitroaromatic compounds were carried out. The formation of corresponding hydroxylamines and amines paved the way for selective and sensitive CE-MS determinations without the need of adding surfactants to the electrophoresis buffer.
authors.affiliation: Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, Regensburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Palatzky
authors.forename: Frank-Michael
authors.initials: FM
authors.lastname: Matysik
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004566:Electrodes; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D005296:Ferrous Compounds / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D019811:Hydroxylamine / Q000032:analysis / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods*
chemical_list: D005296:Ferrous Compounds; C071550:ferrocenemethanol; D019811:Hydroxylamine; D019342:Acetic Acid