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价格低廉、携带方便、适用浓度宽、操作简单快捷、能耗低的离子选择电极在医院、分析实验室、野外等领域得到了越来越广泛的应用。尽管如此,由于PVC膜中存在的离子流严重破坏了更低检测下限的获取,限制了离子选择电极的进一步发展。因此,本文从减小甚至消除PVC膜中存在的离子流角度出发,系统论述了优化PVC膜离子选择电极检测下限的原理和优良策略,根据收集归纳的大量数据定量阐述传感膜组成的优化、电极组装和调制、应用旋转电极以及电流极化处理等对检测下限的优化提升作用,进一步总结出各种方法的改善规律,分析它们的优势和面临的问题。提出在PVC铸膜液中要突破传统配方,减小增塑剂和离子交换剂用量,以抑制传感膜两侧的离子流,同时外加电流补偿处理等也是降低电极检测下限的有效方法,对检测下限的改善最好的可降低5个数量级。这一总结为PVC膜离子选择电极的高性能化明确了研究方向。
Low cost, easy to carry, suitable for wide concentration, simple and fast operation, low energy consumption of ion-selective electrodes in hospitals, analytical laboratories, field and other fields have been more and more widely used. Nevertheless, the further development of ion-selective electrodes has been limited due to the severe deterioration of the lower detection limit achieved by the presence of ion flux in the PVC membrane. Therefore, in this paper, the principle and strategy of optimizing the detection limit of PVC membrane ion selective electrode are systematically discussed in terms of reducing or even eliminating the ion flux existing in PVC membrane. Based on a large amount of data collected and summarized, the optimization of sensing membrane composition is quantitatively described. Electrode assembly and modulation, the application of rotating electrodes and current polarization treatment on the lower limit of detection to enhance the role of further summarized the improvement of various methods, analysis of their advantages and problems. It is suggested that it is an effective way to reduce the lower limit of electrode detection by breaking the traditional formulation, reducing the amount of plasticizer and ion exchanger in the PVC casting solution to restrain the ion current on both sides of the sensing membrane and applying the current compensation treatment. The best lower limit of detection can be reduced by 5 orders of magnitude. This conclusion is clear for the PVC membrane ion selective electrode performance of the research direction.