title: Experimental design optimization of a capillary zone electrophoresis method for the screening of several diuretics and ACE inhibitors.
abstract: Experimental design methodologies are applied to the development of a capillary zone electrophoretic method for the separation of the angiotensin-converting enzyme inhibitor enalapril and its derivative enalaprilat and the diuretics xipamide and hydrochlorothiazide. The effects of pH, buffer concentration, proportion of boric acid in the mixed boric acid-potassium dihydrogen phosphate background electrolyte, temperature, applied voltage, and percentage of organic modifier are studied. Critical factors are identified in a screening design (a 2(6-2) fractional factorial design), and afterwards, optimal conditions for the separation are reached by means of an optimization design (a 2(2) + 2 x 2 + k central composite design). The studied response is the resolution between peaks. The four studied compounds can be separated in less than 3.5 min using an electrolyte of 20mM boric acid-potassium dihydrogen phosphate (75:25, v/v) with 5% MeOH adjusted to pH 8.0 with KOH, at a potential of 30 kV. The detection wavelength and temperature are 206 nm and 35 degrees C, respectively.
authors.affiliation: Departamento de Química Analítica, Facultad de Ciencias, Universidad del País Vasco, Apdo. 644, 48080 Bilbao, Spain. qapalror@lg.ehu.es
authors.forename: U
authors.initials: U
authors.lastname: Akesolo
authors.forename: M I
authors.initials: MI
authors.lastname: Maguregui
authors.forename: L
authors.initials: L
authors.lastname: González
authors.forename: R M
authors.initials: RM
authors.lastname: Jiménez
authors.forename: R M
authors.initials: RM
authors.lastname: Alonso
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000032:analysis*; D000959:Antihypertensive Agents / Q000032:analysis*; D004232:Diuretics / Q000032:analysis*; D019075:Electrophoresis, Capillary / Q000379:methods*; D004656:Enalapril / Q000032:analysis; D015773:Enalaprilat / Q000032:analysis; D006852:Hydrochlorothiazide / Q000032:analysis; D014988:Xipamide / Q000032:analysis
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D004232:Diuretics; D006852:Hydrochlorothiazide; D014988:Xipamide; D004656:Enalapril; D015773:Enalaprilat