Volume: 4, 2025
4th International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland:
ENVIRONMENT – PLANT – ANIMAL – PRODUCT
Abstract number: E011
DOI: https://doi.org/10.24326/ICDSUPL4.E011
Published online: 9 April 2025
ICDSUPL, 4, E011 (2025)
Application of carbon nanocomposite in ammonium ion-selective electrodes – ecology, rapidity and accuracy in one
Klaudia Morawska1*, Cecylia Wardak1
1 Department of Analytical Chemistry, Faculty of Chemistry, University of Marie Curie-Sklodowska, Marii Skłodowskiej-Curie 3, 20-031 Lublin, Poland
* Corresponding author: klaudia.morawska@mail.umcs.pl
Abstract
Ammonium ions (NH4+) in excess are harmful to both fauna and flora. Their high concentrations negatively affect agriculture, inhibiting plant growth and rooting and contributing to the eutrophication of waters. This results in a significant decline in the abundance of plants and aquatic organisms. Ammonium is also oxidized to nitrate and nitrite, which increases the risk of nitrogen leaching into groundwater, leading to contamination. It is crucial to monitor NH4+ content in the environment. This allows for optimizing fertilization strategies, increasing crop efficiency, and minimizing negative environmental impacts. One of the methods used to determine ammonium is potentiometry. The aim of this study was to develop a new and improved version of glassy carbon ion-selective electrode. Glassy carbon-based potentiometric sensors were designed and modified with a composite material to develop a new analytical tool. Sensors selectivity was achieved by applying an ion-sensitive membrane composed of 3% nonactin (ammonium ionophore), 50 mol% potassium tetrakis(4-chlorophenyl) borate relative to the ionophore (0.86% w/w), 30% polyvinyl chloride (which serves as the membrane matrix) and 66.14% bis(1-butylpentyl) adipate (plasticizer). Two pairs of electrodes were prepared: a GCE/ISM, which served as a control electrode, and a modified GCE/NC/ISM electrode, which used a nanocomposite of multi-walled carbon nanotubes (MWCNTs) and carbon nanofibers (CNFs). The GCE/NC/ISM electrode was created by spotting a suspension of MWCNTs: CNFs nanocomposite (1:1) in 15μL tetrahydrofuran before membrane application. After conditioning, a series of tests were conducted to evaluate the analytical parameters of the developed electrodes. As part of these studies, the electrodes’ responses (slope, linearity, and detection limit), stability, and potential reversibility were determined, and the influence of external factors, such as the presence of gases or light was examined. In addition, the selectivity of the electrodes to potential interferers was evaluated. In each case, better results were obtained for modified electrodes – slope 57.18 mV/decade, linearity 1 × 10–1–1 × 10–6 M and potential drift equal 0.35 μV/s. The application of a mediation layer between the membrane and the ammonium electrode substrate not only improved the electrodes’ response but, most importantly, increased the potential’s stability and reversibility. This demonstrates the effective effect of the applied composite as a solid contact.
Keywords: ion-selective electrodes, solid contact, ammonium detection, nanocomposite, multi-walled carbon nanotubes
How to cite
K. Morawska, C. Wardak, 2025. Application of carbon nanocomposite in ammonium ion-selective electrodes – ecology, rapidity and accuracy in one. In: 4th International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland: Environment – Plant – Animal – Product. https://doi.org/10.24326/ICDSUPL4.E011