title: A fast high throughput method for the determination of acidity constants by capillary electrophoresis. 3. Basic internal standards.
abstract: A set of 25 monoprotic bases is proposed as internal standards for pK(a) determination by capillary electrophoresis. The pK(a) of the bases is determined and compared with available literature data. The capillary electrophoresis internal standard method offers numerous advantages over other typical methods for pK(a) determination, especially of analysis time and buffer preparation. However, it requires disposing of appropriate standards with reference pK(a) value. The set of bases established in this work together with the set of acids previously established provide a reference set of compounds with well-determined acidity constants that facilitate the process of selecting appropriate internal standards for fast pK(a) determination by capillary electrophoresis in high throughput screening of pharmaceutical drugs. In addition, the performance of the method when acidic internal standards are used for the determination of acidity constants of basic internal standards has also been tested. Although higher errors may be expected in this case, good agreement is observed between determined and literature values. These results indicate that in most cases structural similarity between the analyte and the internal standard might not be an essential requirement in the internal standard method.
authors.affiliation: Departament de Química Analítica, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Elisabet
authors.initials: E
authors.lastname: Fuguet
authors.forename: Clara
authors.initials: C
authors.lastname: Ràfols
authors.forename: Martí
authors.initials: M
authors.lastname: Rosés
mesh_terms: D000143:Acids / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000379:methods / Q000592:standards*; D057166:High-Throughput Screening Assays / Q000379:methods / Q000592:standards*; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D004364:Pharmaceutical Preparations / Q000032:analysis / Q000302:isolation & purification; D012015:Reference Standards
chemical_list: D000143:Acids; D004364:Pharmaceutical Preparations