Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211, Geneva, Switzerland.
Mikrochim Acta. 2021 Apr 2;188(5):149. doi: 10.1007/s00604-021-04805-1.
The capacitance of the ion-to-electron transducer layer helps to maintain a high potential stability of solid-contact ion-selective electrodes (SC-ISEs), and its estimation is therefore an essential step of SC-ISE characterization. The established chronopotentiometric protocol used to evaluate the capacitance of the single-walled carbon nanotube transducer layer was revised in order to obtain more reliable and better reproducible values and also to allow capacitance to be measured before membrane deposition for electrode manufacturing quality control purposes. The capacitance values measured with the revised method increased linearly with the number of deposited carbon nanotube-based transducer layers and were also found to correlate linearly before and after ion-selective membrane deposition, with correlation slopes close to 1 for nitrate-selective electrodes, to 0.7 and to 0.5 for potassium- and calcium-selective electrodes.
离子-电子转换器层的电容有助于保持固体接触离子选择性电极（SC-ISE）的高电势稳定性，因此其估算 是 SC-ISE 特性描述的一个重要步骤。为了获得更可靠和可重复的结果，并允许在膜沉积之前测量电容以用于电极制造质量控制目的，对用于评估单壁碳纳米管转换器层电容的已建立的计时电位法协议进行了修订。用修订后的方法测量的电容值与沉积的碳纳米管基转换器层的数量呈线性关系，并且在选择性膜沉积前后也呈线性关系，硝酸盐选择性电极的相关斜率接近 1，钾和钙选择性电极的相关斜率分别为 0.7 和 0.5。
