Eka Safitri, Nazaruddin Nazaruddin, Rada Humaira, Muhammad Ridho Afifi, Sitti Saleha, Nor Diyana Md Sani, Rinaldi Idroes, Alizar Ulianas, Nurul Hidayat, Barlah Rumhayati, Eda Yuhana
A Cr3+ ion selective electrode (ISE) based on a polyurethane (PU) membrane from castor oil modified with the active substances 1,10-phenanthroline and graphene was constructed. The ISE consisted of an internal solution with an optimum composition of 0.1 M KCl:Cr(NO3)3 and showed a sensitivity of 20.37 ± 0.51 mV decade−1. Spectroscopic analysis showed that urethane bonds were observed at wave number 3390 cm−1 and 1,10-phenanthroline bonds, proven by the aromatic C=C and C-N bonds, respectively at 1600 cm−1 and 1325 cm−1. The modified PU membranes showed a decrease in crystallinity. However, increased crystallinity was observed when the membrane was in a solution of Cr(III) ions. Furthermore, the membrane exhibited a homogeneous solid outer layer structure and a hollow inner layer. The Cr(III) ISE can measure Cr3+ ion concentrations in the range of 10−11-10-5 M with coefficient of determination, detection limit, and response time of 0.996, 10-11 M, and 180 s, respectively. The ISE showed a stable response in the pH range of 5-7. The selectivity of ISE Cr3+ towards foreign ions did not interfere with measurements with Kij values less than 1. In addition, the Cr3+ ISE demonstrated good reproducibility and repeatability with an average standard deviation value of less than 5%. © 2025 The Electrochemical Society (“ECS”). Published on behalf of ECS by IOP Publishing Limited. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Syiah Kuala, Banda Aceh, 23111, Indonesia; Sanichem Resources Sdn. Bhd., Bandar Estek, Negeri Sembilan, 71060, Malaysia; Department of Pharmacy, Faculty of Mathematics and Natural Sciences, Universitas Syiah Kuala, 20 Banda, Aceh, 23111, Indonesia; Department of Chemistry, Faculty of Mathematics and Natural Sciences, University Negeri Padang, Jl. Prof Dr Hamka Air Tawar Padang Utara, Sumatera Barat, Indonesia; Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Malang, 65145, Indonesia; Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Brawijaya, Malang, Indonesia; Department of Chemistry, Faculty of Science, University Sains Malaysia, Penang, Malaysia
