Dissolved Oxygen
Dissolved oxygen meters are used to quantify the amount of dissolved oxygen (DO) in surface waters or at different stages of wastewater treatment. There are two dissolved oxygen meters in the engineering laboratories. The Orion VersaStar DO meter uses a polarographic probe to determine DO. As DO passes through the semipermeable membrane, a cathode reduces the oxygen molecules creating an electric current. The current travels to an anode and is then measured with an electrochemical sensor to determine DO concentration. The Hach HQ440d DO meter uses an optical probe to determine DO. The optical probe measures the interaction between dissolved oxygen and luminescent dyes within the probe. As oxygen molecules pass through the semipermeable membrane, blue light excites the oxygen molecule’s electrons. As the electrons relax back to the ground state, the luminescence emitted from the electrons are measured correlating to the sample’s DO concentration.
Thermo Scientific Orion VersaStar Pro DO Meter
Hach HQ440d multiprobe DO Meter
