title: A study on the alkaline hydrolysis of isatin-β-thiosemicarbazone by capillary electrophoresis with enhanced sample loadability.
abstract: An analytical potential of capillary zone electrophoresis (CZE) with enhanced sample loadability (a 200nL injection volume) in determination of alkaline hydrolysis products of isatin-β-thiosemicarbazone (IBT), a compound with important biological activity, has been studied. The CZE separation conditions for a complete resolution of transformation products, i.e. 2-aminophenylglyoxalate, 2-(2-aminophenyl)-2-semicarbazonoethane, anthranilate and E-Z geometric isomers of 2-(2-aminophenyl)-2-thiosemicarbazonoethane, have been optimized. CZE separations with UV detection at 240 nm were performed using glycine running buffer at high pH (9.2) and containing an uncharged β-cyclodextrin as a complexing agent. High sensitivity (with detection limits ranging from 0.1 to 1.2 μM), good repeatability (RSD of migration times less than 0.4% and 0.4-3.4% RSD of peak areas) and linearity over two orders of magnitude were achieved for the compounds studied. The employed CZE method, characterized by simple sample handling (only dilution step needed) and total analysis time of less than 15 min, has been applied successfully to time monitoring of the transformation of IBT in alkaline media. Under optimized CZE conditions, the effect of pH of reaction media, implemented by different concentration of NaOH (0.1-100mM), on the course of the alkaline hydrolysis of IBT was studied in this respect, as well.
authors.affiliation: Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina CH2, 842 15 Bratislava, Slovak Republic.
authors.forename: Pavol
authors.initials: P
authors.lastname: Kruk
authors.forename: Henrieta
authors.initials: H
authors.lastname: Stankovičová
authors.forename: Róbert
authors.initials: R
authors.lastname: Bodor
authors.forename: Anton
authors.initials: A
authors.lastname: Gáplovský
authors.forename: Marián
authors.initials: M
authors.lastname: Masár
mesh_terms: D000468:Alkalies / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007510:Isatin / Q000031:analogs & derivatives* / Q000737:chemistry; D007700:Kinetics; D057230:Limit of Detection; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000468:Alkalies; C013578:isatin beta-thiosemicarbazone; D007510:Isatin