title: Clavulanate-selective electrodes--application to pharmaceutical formulations.
abstract: The construction and assessment of a clavulanate anion-selective electrode and its application to the analysis of pharmaceutical formulations by direct potentiometry are described. The electrode, prepared without inner reference solution, was fabricated by use of a PVC membrane, with bis(triphenyl-phosphoranylidene)ammonium clavulanate as ion-exchanger dissolved in 2-nitrophenyl octyl ether as intermediate solvent and p-t-octylphenol as additive. The response of the electrode was linearly dependent on concentration within the range 2.4 x 10(-3)-1 x 10(-1) mol dm(-3) (ionic strength adjusted to 0.1 mol dm(-3)); the slope of the calibration plot was -59.4+/-0.9 mV decade(-1) and the reproducibility +/-0.6 mV day(-1). The response time was less than 20 s. Relative errors were <3.5% when results from analysis by direct potentiometry were compared with those from the reference method.
authors.affiliation: CEQUP/Dep. Química-Física, Fac. de Farmácia, Porto, Portugal.
authors.forename: A M
authors.initials: AM
authors.lastname: Pimenta
authors.forename: C M
authors.initials: CM
authors.lastname: Couto
authors.forename: A N
authors.initials: AN
authors.lastname: Araújo
authors.forename: M C
authors.initials: MC
authors.lastname: Montenegro
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis*; D019818:Clavulanic Acid / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D017736:Ion-Selective Electrodes; D013379:Substrate Specificity; D013535:Suspensions; D013607:Tablets
chemical_list: D000900:Anti-Bacterial Agents; D013535:Suspensions; D013607:Tablets; D019818:Clavulanic Acid