Department of Chemistry, Faculty of Science, Ain Shams University, PO Box 11566, Cairo, Egypt.
Talanta. 2014 Jan;118:147-55. doi: 10.1016/j.talanta.2013.10.011. Epub 2013 Oct 19.
Novel uranyl selective polymeric membrane electrodes were prepared using three different low-cost and commercially available Cyanex extractants namely, bis(2,4,4-trimethylpentyl) phosphinic acid [L1], bis(2,4,4-trimethylpentyl) monothiophosphinic acid [L2] and bis(2,4,4-trimethylpentyl) dithiophosphinic acid [L3]. Optimization and performance characteristics of the developed Cyanex based polymer membrane electrodes were determined. The influence of membrane composition (e.g., amount and type of ionic sites, as well as type of plasticizer) on potentiometric responses of the prepared membrane electrodes was studied. Optimized Cyanex-based membrane electrodes exhibited Nernstian responses for UO₂(2+) ion over wide concentration ranges with fast response times. The optimized membrane electrodes based on L1, L2 and L3 exhibited Nernstian responses towards uranyl ion with slopes of 29.4, 28.0 and 29.3 mV decade(-1), respectively. The optimized membrane electrodes based on L1-L3 showed detection limits of 8.3 × 10(-5), 3.0 × 10(-5) and 3.3 × 10(-6) mol L(-1), respectively. The selectivity studies showed that the optimized membrane electrodes exhibited high selectivity towards UO₂(2+) ion over large number of other cations. Membrane electrodes based on L3 exhibited superior potentiometric response characteristics compared to those based on L1 and L2 (e.g., widest linear range and lowest detection limit). The analytical utility of uranyl membrane electrodes formulated with Cyanex extractant L3 was demonstrated by the analysis of uranyl ion in different real samples for nuclear safeguards verification purposes. The results obtained using direct potentiometry and flow-injection methods were compared with those measured using the standard UV-visible and inductively coupled plasma spectroscopic methods.
新型铀选择性聚合膜电极采用三种不同的低成本和市售的 Cyanex 萃取剂制备，分别为双（2,4,4-三甲基戊基）膦酸[L1]、双（2,4,4-三甲基戊基）单硫膦酸[L2]和双（2,4,4-三甲基戊基）二硫膦酸[L3]。确定了所开发的 Cyanex 基聚合物膜电极的优化和性能特征。研究了膜组成（例如，离子位的数量和类型，以及增塑剂的类型）对制备的膜电极的电位响应的影响。基于优化的 Cyanex 的膜电极对 UO₂（2+）离子在宽浓度范围内表现出 Nernst 响应，具有快速的响应时间。基于 L1、L2 和 L3 的优化膜电极对铀酰离子表现出 Nernst 响应，斜率分别为 29.4、28.0 和 29.3 mV decade（-1）。基于 L1-L3 的优化膜电极的检测限分别为 8.3×10（-5）、3.0×10（-5）和 3.3×10（-6）mol L（-1）。选择性研究表明，优化的膜电极对UO₂（2+）离子表现出高选择性，对大量其他阳离子表现出高选择性。基于 L3 的膜电极表现出优于基于 L1 和 L2 的膜电极的电位响应特性（例如，最宽的线性范围和最低的检测限）。通过直接电位法和流动注射法分析不同真实样品中的铀酰离子，验证了核保障目的的 Cyanex 萃取剂 L3 配方铀膜电极的分析应用。与使用标准紫外可见和电感耦合等离子体光谱法测量的结果相比，直接电位法和流动注射法得到的结果。
