“Determination of Chemical Oxygen Demand (COD) Concentration in Domestic Wastewater Using UV-Vis Spectrophotometry Method Based On The Effect Of Reflux Time And Preservation Time: Penentuan Konsentrasi Chemical Oxygen Demand (COD) Dalam Air Limbah Domestik Menggunakan Metode Spektrofotometri UV-Vis Berdasarkan Pada Pengaruh Waktu Refluks Dan Waktu Pengawetan”. Stannum : Jurnal Sains dan Terapan Kimia 4, no. 1 (May 28, 2022): 13–18. Accessed June 8, 2026. https://journal.ubb.ac.id/index.php/stannum/article/view/2866.