Fabrication of SO42--ISE based on Copolymer of Methyl methacrylate-butyl acrylate (MB28) Thin-film and Graphite Pencil Electrode (GPE)Sagir Alva, I Gusti Ayu Arwati, Siti Aisyah Hasbullah, Aiman Sajidah Abdul Aziz and Deni Shidqi KhaerudiniBIO Web Conf., 159 (2025) 03005DOI: https://doi.org/10.1051/bioconf/202515903005