Ion-Selective Electrodes with Solid Contact Based on Composite Materials: A Review

Abstract

Potentiometric sensors are the largest and most commonly used group of electrochemical sensors. Among them, ion-selective electrodes hold a prominent place. Since the end of the last century, their re-development has been observed, which is a consequence of the introduction of solid contact constructions, i.e., electrodes without an internal electrolyte solution. Research carried out in the field of potentiometric sensors primarily focuses on developing new variants of solid contact in order to obtain devices with better analytical parameters, and at the same time cheaper and easier to use, which has been made possible thanks to the achievements of material engineering. This paper presents an overview of new materials used as a solid contact in ion-selective electrodes over the past several years. These are primarily composite and hybrid materials that are a combination of carbon nanomaterials and polymers, as well as those obtained from carbon and polymer nanomaterials in combination with others, such as metal nanoparticles, metal oxides, ionic liquids and many others. Composite materials often have better mechanical, thermal, electrical, optical and chemical properties than the original components. With regard to their use in the construction of ion-selective electrodes, it is particularly important to increase the capacitance and surface area of the material, which makes them more effective in the process of charge transfer between the polymer membrane and the substrate material. This allows to obtain sensors with better analytical and operational parameters. Brief characteristics of electrodes with solid contact, their advantages and disadvantages, as well as research methods used to assess their parameters and analytical usefulness were presented. The work was divided into chapters according to the type of composite material, while the data in the table were arranged according to the type of ion. Selected basic analytical parameters of the obtained electrodes have been collected and summarized in order to better illustrate and compare the achievements that have been described till now in this field of analytical chemistry, which is potentiometry. This comprehensive review is a compendium of knowledge in the research area of functional composite materials and state-of-the-art SC-ISE construction technologies.

Current advancement in nanomaterial-based emerging techniques for the determination of aminoglycosides antibiotics for antibiotic resistance surveillances

“…Due to their ease of use, affordability, and high sensitivity, these sensors are frequently utilized for antibiotic detection. 165 Ion-selective electrodes (ISEs), which only react to certain ions found in antibiotics, are frequently used in potentiometric sensors for antibiotic detection. Glass membrane electrodes and solid-state electrodes are the two categories into which the ISEs can be divided.…”

Effect of Ion Identity on Capacitance and Ion-to-Electron Transduction in Ion-Selective Electrodes with Nanographite and Carbon Nanotube Solid Contacts

“…Chronopotentiometry to measure the low-frequency capacitance of ISE solid contacts was introduced by Bobacka, initially to study conducting polymer-based transducers but has subsequently been used widely for capacitive high surface area solid contacts, too. ,, The potential change over time as measured in chronopotentiometry allows the capacitance of a sensor to be calculated, with smaller derivatives in the potential versus time plots corresponding to higher capacitances . High capacitances associated with high surface area carbon materials generally correspond to low potential drifts in long-term potentiometric ion sensing, with some transducers displaying drifts ≤10 μV/h. ,, We note, however, that although a high capacitance is important for long-term stability of the measured potential under otherwise ideal conditions, other features of the sensors can affect observed potential stabilities, such as the hydrophobicity of ionic sites and ionophores, the stability of ionophore complexes, and the underlying electrode material. ,− …”

Application of ionic liquids in ion‐selective electrodes and reference electrodes: A review

“…[30] Before a material can serve as a solid contact layer, it must meet certain requirements and exhibit (1) sufficiently high hydrophobic properties, (2) chemical inertness, (3) chemical stability, (4) good conductivity and electrical capacitance. [31] The most commonly used components of intermediate layers include carbon materials, e. g. graphene, [32] multi-walled carbon nanotubes (MWCNTs), [33][34][35] single-walled carbon nanotubes (SWCNTs), [36][37][38] fullerenes, [39] carbon nanofibers (CNFs); [40] con- ducting polymers, e. g. poly(3,4-ethylenedioxythiophene) (PEDOT), [41] polyaniline (PANI), [26,40,42] poly(3-octylthiophene) (POT); [43,44] nanoparticles of metals and metal oxides, e. g. nanoparticles of platinum, [28] silver, [45] copper oxides; [29] ionic liquids, [46] as well as composite materials consisting of two or more of the materials listed above. [31,47,48] In order to improve the performance of ion-selective electrodes, they are not only modified by the introduction of an intermediate layer (in liquid-contact ISEs this is not done, because solid contact does not occur there), but also additional components are introduced as additives to the membrane mixtures.…”