Overcoming the problem of non-ideal liquid ion exchanger selectivity in microelectrode ion flux measurements
Overcoming the problem of non-ideal liquid ion exchanger selectivity in microelectrode ion flux measurements
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DOI：
10.1007/s00232-004-0719-2
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发表时间：
2004-11-01
影响因子：
2.4
通讯作者：
Shabala, S
中科院分区：
文献类型：
--
作者：
Knowles, A;Shabala, S
离子选择性微电极是研究动物和植物组织细胞膜生物学各个方面的有力工具。然而，该技术的进一步应用在很大程度上受到用于制备离子通量测量的微电极的液体离子交换剂的非理想选择性的问题的限制。因为这个问题。在许多商业液体离子交换器中，微电极不能区分感兴趣的离子和其它干扰离子（例如，Mg 2+和Ca 2+、Na+和K+），从而导致不准确的浓度读数，并因此导致不准确的通量计算。在这项工作中，我们表明，现有的分析程序，以克服这个问题，使用倒置的尼科尔斯基-艾森曼方程，是不充分的。并提出了一种可直接应用于用市售液体离子交换剂获得的数据的替代分析方法。我们表明，这种替代的程序允许准确测量的离子浓度与非理想的离子选择性微电极在干扰离子的存在下，并说明该方法通过直接实验使用Ca 2+和Mg 2+作为“案例研究”。文中还列举了几个实例，进一步说明了该方法在植物盐敏感性研究中的实际应用。渗透压和活性氧的压力。
Ion-selective microelectrodes are a powerful tool in studies on various aspects of cell membrane biology in both animal and plant tissues. Further application of this technique is, however, limited to a large extent by the problem of non-ideal selectivity of the liquid ion exchanger used in the preparation of microelectrodes for ion flux measurements. Because of this problem. which is persistent In many commercial liquid ion exchangers, the microelectrode does not discriminate between the ion of interest and other interfering tons (for example, Mg2+ and Ca2+, Na+ and K+) thereby leading to inaccurate concentration readings and, consequently, inaccurate flux calculations. In this work we show that the existing analytical procedure to overcome this problem, using the inverted Nicolsky-Eisenman equation, is Inadequate. and suggest an alternative analytical procedure that can be applied directly to the data obtained with commercially available liquid ion exchangers. We show that this alternative procedure allows accurate measurement of ionic concentrations with non-ideal ion-selective microelectrodes in the presence of interfering ions, and Illustrate the method by direct experiment using Ca2+ and Mg2+ as a "case study". Several more examples are given, further illustrating practical applications of the method for study of plant responses to salinity.. osmotic and reactive oxygen species stresses.