Sensitivity and working range of backside calibration potentiometry.
Sensitivity and working range of backside calibration potentiometry.
复制标题
背面校准电位的灵敏度和工作范围。
DOI：
10.1021/ac071248a
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发表时间：
2007
影响因子：
7.4
通讯作者：
Bakker,Eric
中科院分区：
文献类型：
--
作者：
Ngeontae,Wittaya;Xu,Yida;Xu,Chao;Aeungmaitrepirom,Wanlapa;Tuntulani,Thawatchai;Pretsch,Ernö;Bakker,Eric
电位传感的一个新的方向，称为背面校准电位法，最近推出。它利用了这样一个事实，即在不存在跨支撑液体离子选择性膜的离子-离子载体络合物浓度梯度的情况下，搅拌效应消失。该方法特别适用于无法在样品中进行重新校准的测量，例如远程监控应用。在此，建立了一个理论模型来预测该方法的工作浓度范围。铅（II）选择性Celgard膜在这里使用的H+作为主要的干扰离子。搅拌和未搅拌的溶液的电动势的差异进行了测量，并发现作为样品Pb 2+浓度的函数的电动势变化的幅度表现出一个钟形，跨越103个数量级。干扰离子的浓度和膜的选择性被证明是影响工作范围的重要因素。较小的比率的初级离子浓度在两个水侧的膜得到较小的电动势差值，和电动势的变化仍然可以观察到对数浓度比为0.05。所有实验结果与理论模型的相关性令人满意。
A new direction in potentiometric sensing, termed backside calibration potentiometry, was recently introduced. It makes use of the fact that the stir effect disappears in the absence of an ion−ionophore complex concentration gradient across supported liquid ion-selective membranes. This method is especially suitable for measurements in which recalibration in the sample is not feasible, such as in remote monitoring applications. Here, a theoretical model is established to predict the working concentration range of the method. Lead(II)-selective Celgard membranes were used here with H+as the dominant interfering ions. The emf difference for stirred and unstirred solutions was measured, and the magnitude of this emf change as a function of the sample Pb2+concentration was found to exhibit a bell shape that spans ∼3 orders of magnitude. The concentration of interfering ions and the selectivity of the membrane were demonstrated to be important factors that affect the working range. Smaller ratios of primary ion concentrations at both aqueous sides of the membrane gave smaller emf difference values, and emf changes could still be observed with a logarithmic concentration ratio of 0.05. All experimental results correlated satisfactorily with the theoretical model.