Capillary electrophoresis (CE) coupled to a capacitively coupled contactless conductivity detector (C 4 D) was used for the determination in a single analysis of a pharmaceutical drug and its counter-ion. Dual-opposite end injection (DOI) was used to introduce hydrodynamically the analytes at each end of the capillary. No modification of the commercial apparatus is required. After applying the voltage, the cations and anions migrate from each end of the capillary in opposite directions toward the detector placed near the cathode outlet. The electrophoretic conditions were initially developed with three test drugs (chlorpheniramine maleate, metoprolol tartrate, clomiphene citrate) and then applied to two Vinca alkaloids (catharanthine sulfate, vinorelbine ditartrate). The 10 mM histidine-50 mM acetic acid buffer (pH 4.1)-methanol 90:10 (v/v) electrolyte was suitable for the analysis of these high or medium mobile anions by CE-C 4 D due to its low conductivity background and high buffer capacity. Finally, the CE procedure developed was successfully validated for catharanthine sulfate. The method developed herein is fast (\10 min) and accurate (repeatability on migration time \ 0.6% and peak areas \ 1.3%, n = 6).

a b s t r a c tIn this work the dielectric behaviour and main features of the phase transition of BaTiO 3 and Ba 0.99 Er 0.01 TiO 3 ceramics were carefully investigated. The temperature and frequency dependences of the dielectric properties of erbium doped BaTiO 3 ceramics were measured in the 25-225 • C and 100 Hz to 10 MHz ranges, respectively. From this study, a dielectric anomaly in the ferroelectric-paraelectric phase transition of the Ba 0.99 Er 0.01 TiO 3 ceramic was observed. The features of the samples phase transition were analysed by using Curie-Weiss, Santos-Eiras' and order parameter local phenomenological models. In the BaTiO 3 system, all models showed a normal phase transition, while was not possible to establish the character of the phase transition in the Ba 0.99 Er 0.01 TiO 3 system. The relaxation parameters of conductive processes for the study ferroelectric materials, analysed in the time domain, did not show any influence on the ferroelectric-paraelectric phase transition. Finally, it was demonstrated that the anomaly observed on the phase transition of the erbium doped BaTiO 3 ceramics is associated with the processes that results in the PTCR effect.

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