Department of Chemistry, Faculty of Science, Fayoum, Cairo University, Fayoum Branch, Fayoum, Egypt.
Talanta. 2003 May 1;59(6):1259-66. doi: 10.1016/S0039-9140(03)00035-3.
A new prenalterol (Pr) ion-selective PVC membrane electrode based on the ion-pair complex of Pr with sodium tetraphenylborate was prepared and its performance characteristics were studied. The electrode exhibited a linear response with a good Nernstian slope over a relatively wide range of concentration. The electrode whose membrane was made of 8.0% (w/w) of ion pair, 49.5% (w/w) of dioctyl phthalate (DOP) and 43.5% (w/w) of PVC showed characteristics higher than those obtained with the other ones, namely, slope of 56.3 mV per concentration decade, at 25 degrees C; usable concentration range 1.2x10(-5)-3.2x10(-2) M prenalterol; response time </=20 s. Up to 24 h continuous soaking, the calibration graph slope was constant at 56.0 mV per concentration decade, at 25 degrees C, then it decreased gradually as the time of soaking increases reaching 41 mV per decade after 11 days. The changes in pH did not affect the electrode performance within the range 2.2-7.5. The standard electrode potentials were determined at different temperatures and used to calculate the isothermal coefficient of the electrode. The electrode showed very good selectivity for Pr with respect to a large number of inorganic and organic cations. The standard addition method and potentiometric titration were used to determine Pr in pure solutions and in pharmaceutical formulations. The relative standard deviations (R.S.D.) of the three methods used for the determination of prenalterol in pharmaceutical formulations were 0.8, 2.1 and 1.9% of the extrapolation, standard addition and potentiometric methods, respectively.
一种基于 Pr 与四苯硼酸钠离子对复合物的新型prenalterol（Pr）离子选择性 PVC 膜电极已被制备，并研究了其性能特征。该电极在较宽浓度范围内表现出线性响应，具有良好的能斯特斜率。其膜由 8.0%（w/w）的离子对、49.5%（w/w）的邻苯二甲酸二辛酯（DOP）和 43.5%（w/w）的 PVC 组成的电极表现出优于其他电极的特性，即在 25°C 时斜率为 56.3 mV 每浓度十年；可使用的浓度范围为 1.2x10(-5)-3.2x10(-2) M prenalterol；响应时间 </=20 s。在 25°C 下，连续浸泡长达 24 小时后，校准曲线斜率在 56.0 mV 每浓度十年时保持恒定，然后随着浸泡时间的增加逐渐下降，11 天后降至每十年 41 mV。pH 值的变化在 2.2-7.5 范围内不会影响电极性能。在不同温度下确定了标准电极电位，并用于计算电极的等温系数。该电极对 Pr 具有很好的选择性，相对于大量的无机和有机阳离子。标准加入法和电位滴定法用于测定纯溶液和药物制剂中的 Pr。用于测定药物制剂中prenalterol 的三种方法（外推法、标准加入法和电位滴定法）的相对标准偏差（R.S.D.）分别为 0.8%、2.1%和 1.9%。
