Robust fabrication of nanomaterial-based all-solid-state ion-selective electrodes

Screen-printed sensors for efficient potentiometric analysis of tolperisone hydrochloride in presence of its co-formulated drugs

Researchers seeking for green chemistry to help safeguard and boost the economy and the environment by discovering unique ways to decrease waste and find substitutes for dangerous chemicals. In this study, a green potentiometric ion-selective electrode (ISE) was developed for measurement of tolperisone HCl (TOLP) in bulk and Pharmaceutical dosage forms in presence of diclofenac sodium and paracetamol as co-formulated drugs. This paper presents the manufacture and characterization of a disposable potentiometric ion-selective strip with an enhanced detection limit for (TOLP) measurement in its tablet dosage form either alone or in presence of the co-formulated drugs. Numerous ion pairs (IPs), such as TOLP-tetraphenylborate (TOLP-TPB), TOLP-phosphotungstic acid (TOLP-PTA), and TOLP-ammonium Reinecke (TOLP- RKT) are tested in presence of different plasticizers. The optimal potentiometric response with a near Nernstian slope of 55.949 mV/decade was achieved within a linear concentration range of 5 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× 10^–5 − 1 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× 10^–2 M using (PTA) and ortho nitrophenyl octyl ether (o-NPOE) as a plasticizer. The effect of the nanoparticles on the membrane stability was studied using the graphene nanoplatelets which have an effective role in the enhancement of some constructed sensors stability. Finally, the developed technique is validated for the estimation of TOLP with high accuracy and precision.

Ion-to-electron capacitance of single-walled carbon nanotube layers before and after ion-selective membrane deposition

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.

Textile-based wearable solid-contact flexible fluoride sensor: Toward biodetection of G-type nerve agents

Rising global concerns posed by chemical and biological threat agents highlight the critical need to develop reliable strategies for the real-time detection of such threats. While wearable sensing technology is well suited to fulfill this task, the use of on-body devices for rapid and selective field identification of chemical agents is relatively a new area. This work describes a flexible printed textile-based solid-contact potentiometric sensor for the selective detection of fluoride anions liberated by the biocatalytic hydrolysis of fluorine-containing G-type nerve agents (such as sarin or soman). The newly developed solid-contact textile fluoride sensor relies on a fluoride-selective bis(fluorodioctylstannyl)methane ionophore to provide attractive analytical performance with near-Nernstian sensitivity and effective discrimination against common anions, along with excellent reversibility and repeatability for dynamically changing fluoride concentrations. By using stress-enduring printed inks and serpentine structures along with stretchable textile substrates, the resulting textile-based fluoride sensor exhibits robust mechanical resiliency under severe mechanical strains. Such realization of an effective textile-based fluoride-selective electrode allowed biosensing of the nerve-agent simulant diisopropyl fluorophosphate (DFP), in connection to immobilized organophosphorus acid anhydrolylase (OPAA) or organophosphorus hydrolase (OPH) enzymes. A user-friendly portable electronic module transmits data from the new textile-based potentiometric biosensor wirelessly to a nearby smartphone for alerting the wearer instantaneously about potential chemical threats. While expanding the scope of wearable solid-contact anion sensors, such a textile-based potentiometric fluoride electrode transducer offers particular promise for effective discrimination of G-type neurotoxins from organophosphate (OP) pesticides, toward specific field detection of these agents in diverse defense settings.

Recent advances in solid-contact ion-selective electrodes: functional materials, transduction mechanisms, and development trends

This article presents a comprehensive overview of recent progress in the design and applications of solid-contact ion-selective electrodes (SC-ISEs).