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Ion-selective electrodes are a popular analytical tool useful in the analysis of cations and anions in environmental, industrial and clinical samples. This paper presents an overview of new materials used for the preparation of anion-sensitive ion-selective electrodes during the last five years. Design variants of anion-sensitive electrodes, their advantages and disadvantages as well as research methods used to assess their parameters and analytical usefulness are presented. The work is divided into chapters according to the type of ion to which the electrode is selective. Characteristics of new ionophores used as the electroactive component of ion-sensitive membranes and other materials used to achieve improvement of sensor performance (e.g., nanomaterials, composite and hybrid materials) are presented. Analytical parameters of the electrodes presented in the paper are collected in tables, which allows for easy comparison of different variants of electrodes sensitive to the same ion. [ABSTRACT FROM AUTHOR]

This work proposes new carbon materials for intermediate layers in solid-contact electrodes sensitive for potassium ions. The group of tested materials includes electrospun carbon nanofibers, electrospun carbon nanofibers with incorporated cobalt nanoparticles and hierarchical nanocomposites composed of carbon nanotubes deposited on nanofibers with different metal nanoparticles (cobalt or nickel) and nanotube density (high or low). Materials were characterized using scanning electron microscopy and contact angle microscopy. Electrical parameters of ready-to-use electrodes were characterized using chronopotentiometry and electrochemical impedance spectroscopy. The best results were obtained for potassium electrodes with carbon nanofibers with nickel-cobalt nanoparticles and high density of nanotubes layer: the highest capacity value (330 µF), the lowest detection limit (10−6.3 M), the widest linear range (10−6–10−1) and the best reproducibility of normal potential (0.9 mV). On the other hand the best potential reversibility, the lowest potential drift (20 μV·h−1) in the long-term test and the best hydrophobicity (contact angle 168°) were obtained for electrode with carbon nanofibers with cobalt nanoparticles and high density of carbon nanotubes. The proposed electrodes can be used successfully in potassium analysis of real samples as shown in the example of tomato juices. [ABSTRACT FROM AUTHOR]

Nitrates are a group of compounds widely distributed in the natural environment with many applications in various industries. Due to their ambiguous impact on the human body and suspicions of their carcinogenic activity, they have been very popular for decades and are the subject of research by many scientists in the field of medicine, biology and chemistry. Due to the need to monitor their content in environmental and food samples, various methods for their determination are developed. This paper proposes the use of a nitrate ion‐sensitive ion selective electrode with a membrane containing as the active ingredient a new cobalt(II) complex with 4,7‐diphenyl‐1,10‐phenanthroline (Bphen) of the formula Co(Bphen)2(NO3)2(H2O)2. The obtained sensor showed the theoretical slope of the characteristic curve, a wide measuring range, as well as short response time and very good potential stability. It was successfully used for the determination of nitrates in real samples: in mineral water, tap water and river water from eastern Poland. [ABSTRACT FROM AUTHOR]

A simple, fast and cheap method for monitoring copper and nitrate in drinking water and food products using newly developed solid contact ion-selective electrodes is proposed. Determination of copper and nitrate was performed by application of multiple standard additions technique. The reliability of the obtained results was assessed by comparing them using the anodic stripping voltammetry or spectrophotometry for the same samples. In each case, satisfactory agreement of the results was obtained, which confirms the analytical usefulness of the constructed electrodes. [ABSTRACT FROM PUBLISHER]

A new type of cadmium ion-selective electrode with solid contact with the implementation of multi-walled carbon nanotubes (MWCNTs) as the ion-to-electron transducer and ionic liquid: 1-butyl-3-methylimidazolium hexafluorophosphate (BMImPF 6 ) as a lipophilic ionic additive was reported. The proposed electrode exhibits low detection limit and short response time but has stable, reproducible and reversible potential. The presence of the interfacial water film was evaluated by the potentiometric water layer test and electrical properties of the membrane were studied by electrochemical impedance spectroscopy. [ABSTRACT FROM AUTHOR]

A simple, fast and cheap method of preparation of solid contact nitrate ion-selective electrode is proposed. The electrode membrane phase consist of only three components: PVC, plasticizer and ionic liquid (IL).The ionic liquid trihexyltetradecylphosphonium chloride is used in triple function as ionophore, as lipophilic ionic component in order to reduce membrane resistance, and as transducer media in order to stabilize the potential of internal Ag/AgCl electrode. The electrical properties of the membrane were studied by electrochemical impedance spectroscopy and the influence of the interfacial water film was evaluated by potentiometric water layer test. [ABSTRACT FROM AUTHOR]

The ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate is used as a new lipophilic ionic additive in the polymeric membrane of a solid contact type lead ion-selective electrode. The membrane is deposited on an internal glassy carbon electrode with poly(3-octyl)thiophene as an intermediate layer. The sensor exhibits good analytical parameters: low detection limit of 3.5x10-9 mol L-1, Nernstian response slope of 29.8 mV/decade, a wide concentration range of 1x10-8-1x10-1 mol L-1, short response time of 7 s, and relatively long lifetime of 100 days. The proposed sensor has a working pH range of 4.0-6.9 and excellent selectivity for Pb(II) ions over a wide variety of other metal ions. The efficiency of the proposed sensor was demonstrated by its application for direct determination of Pb2+ ions in real water samples. [ABSTRACT FROM AUTHOR]

An optimal new PVC membrane sensor for Cd2+ ions based on TRIAR3-(2′,4′ dihydroxyphenylazo-1 '')-1,2,4 triazol as the active substance was prepared. Its basic analytical parameters such as slope characteristics; detection limit; lifetime; response time; selectivity for zinc, nickel, cobalt, calcium, copper, barium, magnesium, manganese, potassium and sodium ions, as well as the dependence of the electrode potential on pH were established. The proposed membrane sensor can be used in flow injection potentiometric analysis of cadmium ions. [Copyright &y& Elsevier]

Carbon nanotubes have enjoyed unflagging popularity in recent years. They are successfully used in many fields of science, including potentiometry for the construction of ion selective electrodes with solid contact. A new type of SC-ISEs sensitive to nitrate(V) ions using multiwalled carbon nanotubes-ionic liquid nanocomposite was prepared. The effect of the kind of carbon nanotubes on the parameters of SC-ISEs was investigated. The study compares, among others, detection limits, sensitivity and linearity ranges of characteristic curves, and stability of the potential measured for the tested electrodes. Electrochemical impedance spectroscopy and chronopotentiometric techniques were also used as research methods. It was found that the type of carbon nanotubes included in the nanocomposite influences both the metrological and electrical parameters of the obtained solid contact nitrate ion-selective electrode. • Various carbon nanotubes-ionic liquid nanocomposites were tested as a new membrane component. • New simple and cheap nitrate all solid state ion-selective electrode was prepared. • Type of nanocomposite used impacts essentially on electrode performance. [ABSTRACT FROM AUTHOR]

Composition of a polymeric potential-determining phase for the ibuprofen selective electrode was determined. The different possibilities of using various quaternary ammonium salts — dimethyldidecylammonium bromide, methyltrioctylammonium chloride, tetraoctylammonium chloride and methyltrioctyloammonium 2-(4-isobuthylphenyl) priopionate—as anion exchangers in polymer membranes of ibuprofen electrodes were examined. The following basic electrode parameters were investigated: measurement range, slope, limit of detection, lifetime, dependence of the electrode potential on pH and selectivity coefficients in relation to some organic and inorganic anions. [Copyright &y& Elsevier]

In recent years, various types of nanomaterials and nanoparticles have been very popular, also in analytical chemistry for sensors preparation. Ion-selective electrodes with solid contact were constructed, in which a layer of nanoparticles of selected metal oxides (zinc, copper and iron oxides) obtained by pulsed laser liquid ablation (PLAL) was placed between the glassy carbon solid electrode material and the ion-selective membrane. The basic analytical parameters of the obtained sensors were determined using potentiometric methods. Additionally, the electrochemical impedance spectroscopy method (EIS) was also used to investigate the electrical properties of the sensors. The obtained results were compared for all types of electrodes, both modified and unmodified, in order to investigate the effect of the type of nanoparticles and the thickness of their layer used as solid contact. It was found that the addition of metal oxide nanoparticles improved the analytical parameters of the sensors, mainly the potential stability and electrical parameters. The best results were obtained for an electrode with an intermediate layer of zinc oxide nanoparticles. In this case, a slope of −56.07 mV/dec, a linearity range of 1 × 10−5 – 1 × 10−1 mol L−1 and a limit of detection of 3.66 × 10−6 mol L−1 were obtained. Particularly noteworthy is the significant improvement in the stability of the potential of this electrode and the long life of more than 5 months. [Display omitted] • Properties of metal oxides nanoparticles obtained by laser ablation is described. • First use of them as solid contact in ion-selective electrodes is presented. • Type of nanoparticles used impacts essentially on electrode performance. [ABSTRACT FROM AUTHOR]