Comparison of two low flow interfaces for measurement of mobilities and stability constants by affinity capillary electrophoresis-mass spectrometry

0493561 - ÚOCHB 2019 RIV NL eng J - Článek v odborném periodiku
Konášová, Renáta - Koval, Dušan - Jaklová Dytrtová, Jana - Kašička, Václav
Comparison of two low flow interfaces for measurement of mobilities and stability constants by affinity capillary electrophoresis-mass spectrometry.
Journal of Chromatography A. Roč. 1568, Sep 21 (2018), s. 197-204. ISSN 0021-9673. E-ISSN 1873-3778
Grant CEP: GA ČR(CZ) GA15-01948S; GA ČR(CZ) GA17-10832S; GA ČR(CZ) GA17-12648S
Institucionální podpora: RVO:61388963
Klíčová slova: affinity capillary electrophoresis * CE-MS interface * crown ether complexes * electrospray ionization * mass spectrometry * stability constant
Obor OECD: Analytical chemistry
Impakt faktor: 3.858, rok: 2018

Affinity capillary electrophoresis (ACE) is typically used for the determination of stability constant, K-st, of weak to moderately strong complexes. Sensitive detection such as mass spectrometry (MS) is required for extension of ACE methodology for estimation of K-st of stronger complexes. Consequently, an efficient interface for hyphenation of CE with MS detection is necessary. For evaluation of interfaces for electrospray ionization mass spectrometric (ESI/MS) detection in ACE conditions, potassium-crown ether complexation was used as model system. The effective mobilities of the crown ether ligands and the K-st of their potassium complexes were measured/determined by ACE-ESI/MS using two lab-made interfaces: (i) a sheathless porous tip CE-ESI/MS interface and (ii) a nano-sheath liquid flow CE-ESI/MS interface, and, in turn, compared with those obtained by ACE with UV spectrophotometric detection. Apparent stability constant of potassium-crown ether complexes in 60/40 (v/v) methanol/water mixed solvent, pH* 5.5, was about 1300 L/mol for dibenzo-18-crown-6, 1600 L/mol for benzo-18-crown-6 and 5200 L/mol for 18-crown-6 ligands, respectively. It was observed that electrophoretic mobilities from CE-MS experiments differ from reference values determined by UV detection by similar to 7% depending on the CE-MS interface used. Good agreement of CE-MS and CE-UV data was achieved for nano-sheath liquid flow interface, in which the spray potential and the CE separation potential can be effectively decoupled. As for sheathless porous tip interface, a correction procedure involving a mobility marker has been proposed. It provides typically only ca. 1% difference of effective mobilities and K-st values obtained from CE-MS data as compared to those received by the reference ACE-UV method.
Trvalý link: http://hdl.handle.net/11104/0286906