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 [Internet]. 2022 May 28 [cited 2026 Apr. 25];4(1):13-8. Available from: https://www.journal.ubb.ac.id/index.php/stannum/article/view/2866