Frag Eman Y Z, Mohamed Gehad G, Khalil Mohamed M, Hwehy Mohammad M A
Chemistry Department, Faculty of Science, Cairo University, Giza 12613, Egypt.
Int J Anal Chem. 2011;2011:604741. doi: 10.1155/2011/604741. Epub 2011 Oct 13.
This study compares between unmodified carbon paste (CPE; the paste has no ion pair) and polyvinyl chloride (PVC) membrane selective electrodes that were used in potentiometric determination of ketotifen fumarate (KTF), where sodium tetraphenylborate (NaTPB) was used as titrant. The performance characteristics of these sensors were evaluated according to IUPAC recommendations which reveal a fast, stable, and linear response for KTF over the concentration range of 10(-7) to 10(-2) mol L(-1). The electrodes show Nernstian slope value of 52.51 ± 0.20 and 51.51 ± 0.25 mV decade(-1) for CPE and PVC membrane electrodes at 30°C, respectively. The potential is nearly stable over the pH range 3.0-6.0 and 2.0-7.0 for CPE and PVC membrane electrodes, respectively. Selectivity coefficient values towards different inorganic cations, sugars, and amino acids reflect high selectivity of the prepared electrodes. The electrodes responses at different temperatures were also studied, and long operational lifetime of 12 and 5 weeks for CPE and PVC membrane electrodes, respectively, were found. These are used for determination of ketotifen fumarate using potentiometric titration, calibration, and standard addition methods in pure samples, its pharmaceutical preparations (Zaditen tablets), and biological fluid (urine). The direct potentiometric determination of KTF using the proposed sensors gave recoveries % of 98.97 ± 0.53 and 98.62 ± 0.74 with RSD 1.42 and 0.63% for CPE and PVC membrane selective electrodes, respectively. Validation of the method shows suitability of the proposed sensors for use in quality control assessment of KTF. The obtained results were in a good agreement with those obtained using the reported spectrophotometric method.
本研究比较了未改性碳糊电极（CPE；该糊剂无离子对）和聚氯乙烯（PVC）膜选择性电极，它们用于电位滴定法测定富马酸酮替芬（KTF），其中四苯硼酸钠（NaTPB）用作滴定剂。根据国际纯粹与应用化学联合会（IUPAC）的建议对这些传感器的性能特征进行了评估，结果表明在10⁻⁷至10⁻² mol·L⁻¹的浓度范围内，KTF具有快速、稳定且线性的响应。在30°C时，CPE和PVC膜电极的能斯特斜率值分别为52.51±0.20和51.51±0.25 mV·dec⁻¹。对于CPE和PVC膜电极，电位分别在pH范围3.0 - 6.0和2.0 - 7.0内几乎稳定。对不同无机阳离子、糖类和氨基酸的选择性系数值反映了所制备电极的高选择性。还研究了电极在不同温度下的响应，发现CPE和PVC膜电极的操作寿命分别长达12周和5周。这些电极用于通过电位滴定、校准和标准加入法测定纯样品、其药物制剂（扎迪特片）和生物流体（尿液）中的富马酸酮替芬。使用所提出的传感器直接电位法测定KTF时，CPE和PVC膜选择性电极得到的回收率分别为98.97±0.53%和98.62±0.74%，相对标准偏差分别为1.42%和0.63%。该方法的验证表明所提出的传感器适用于KTF的质量控制评估。所得结果与使用报道的分光光度法获得的结果高度一致。
