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All Journal Hydrogen: Jurnal Kependidikan Kimia
Okta Suryani
Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Negeri Padang,Jl.Prof. Dr.Hamka Air Tawar Barat, Padang, Indonesia
Chemistry Education

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Voltammetric Detection of Zn2+ Ions Using a Glassy Carbon Electrode Modified with Napa-Soil-Derived NiAl₂O₄ Dhea Septiani; Mawardi Mawardi; Indang Dewata; Umar Kalmar Nizar; Okta Suryani
Hydrogen: Jurnal Kependidikan Kimia Vol. 14 No. 2 (2026): April 2026
Publisher : Universitas Pendidikan Mandalika

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33394/hjkk.v14i2.20367

Abstract

This study reports the development of a glassy carbon electrode (GCE) modified with NiAl2O4 derived from napa soil for the voltammetric detection of Zn2+ ions. The modified electrode was prepared using a drop-casting method and characterized in 4.0 mM K3[Fe(CN)6] with 0.1 M KCl as the supporting electrolyte. The results showed an increase in oxidation peak current from 19.93 µA (bare GCE) to 26.80 µA and reduction peak current from −19.03 µA to −24.29 µA after modification, indicating enhanced electron transfer. Zn2+ detection was carried out in the concentration range of 1–3 mM, where the reduction peak current increased from −85.49 µA to −170.83 µA with increasing concentration. A linear relationship between concentration and current response was obtained with a regression equation of y = -42.67x – 40.42 and a correlation coefficient (R2 = 0.9907), indicating good linearity of the sensor. The limit of detection (LOD) was calculated to be 0.21 mM. Among the tested supporting electrolytes, 0.1 M KCl provided the highest and most stable current response. Although the modified electrode shows improved performance, the detection range is still limited to the millimolar level, and further studies are required to evaluate selectivity, reproducibility, and applicability in real samples. These findings demonstrate the potential of napa-soil-derived NiAl2O4 as a sustainable and cost-effective material for electrochemical sensing applications.
Voltammetric Detection of Cu²⁺ Using a Napa Soil-Derived NiAl₂O₄/MWCNT-Modified Glassy Carbon Electrode Ihya Zakira Sani; Mawardi Mawardi; Desy Kurniawati; Miftahul Khair; Okta Suryani
Hydrogen: Jurnal Kependidikan Kimia Vol. 14 No. 3 (2026): June 2026
Publisher : Universitas Pendidikan Mandalika

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33394/hjkk.v14i3.21279

Abstract

Copper ions (Cu²⁺) are essential trace elements but may become toxic at elevated concentrations, requiring reliable monitoring methods. In this study, a NiAl₂O₄/MWCNT-modified glassy carbon electrode (GCE) derived from napa soil was developed for the voltammetric determination of Cu²⁺ ions. The modified electrode was prepared by combining NiAl₂O₄ synthesized from napa soil with multi-walled carbon nanotubes (MWCNTs) through a drop-casting technique. Electrochemical characterization demonstrated that the incorporation of NiAl₂O₄ and MWCNTs significantly enhanced the electrochemical performance of the electrode by improving electron-transfer efficiency and increasing the electroactive surface area. The modified electrode exhibited a strong voltammetric response toward Cu²⁺ ions, while HClO₄ was identified as the most suitable supporting electrolyte among the investigated media. Selectivity studies showed that Cu²⁺ remained detectable in the presence of Pb²⁺, although partial signal suppression was observed at higher Pb²⁺ concentrations. These findings indicate that the NiAl₂O₄/MWCNT-modified GCE is a promising low-cost and sustainable platform for Cu²⁺ determination in aqueous environments.
Co-Authors Desy Kurniawati Dhea Septiani Ihya Zakira Sani Indang Dewata Mawardi Mawardi Miftahul Khair Umar Kalmar Nizar