Experiments on the use of oxygen meters
Experiments on the use of oxygen meters
(i) Oxygen electrode: It consists of a 10μ diameter platinum wire as the cathode, enclosed in a glass tube with a cross section exposed. Silver-silver chloride is used as the anode, which is covered with a tetrafluoroplastic casing and a polyethylene film of 15-20μ. A 0.5 NKCl solution was placed between the electrode and the casing film. A polarization voltage of 0.7 V was applied to the anode and cathode.
(ii) Determination principle: platinum electrode close to the film, through the film and the diffusion of O2 dissolved in the solution near the electrode, under a certain polarization voltage dissolved oxygen molecules are reduced.
Operation method
Experiments on the use of oxygen meters
Principle
(i) Oxygen electrode: It consists of a 10μ diameter platinum wire as the cathode, enclosed in a glass tube with a cross section exposed. Silver-silver chloride is used as the anode, which is covered with a tetrafluoroplastic casing and a polyethylene film of 15-20μ. A 0.5 NKCl solution was placed between the electrode and the casing film. A polarization voltage of 0.7V is applied to the anode and cathode. (ii) Determination principle: platinum electrode close to the film, through the film and the diffusion of O2 dissolved in the solution near the electrode, under a certain polarization voltage dissolved oxygen molecules are reduced: and to the cathode platinum wire as the center of the formation of the diffusion layer, the diffusion of this current and the partial pressure of oxygen in the sample to be measured into a linear relationship. The oxygen current signal generated by electrolysis on the platinum electrode is amplified by a transistor amplifier, and the change in partial pressure of oxygen in the sample is recorded by a recorder. Move 1. Installation of electrodes: Open the screw plug of the electrode casing and add 0.5NKCl solution into the electrode casing. Tighten the screw plug of the electrode sleeve again and wipe the solution outside. Insert the electrode plug into the "input" socket of the oxygen meter; insert the recorder plug into the "output" socket of the oxygen meter and turn on the recorder power (as shown in the figure). For more product details, please visit Aladdin Scientific website.
2. Turn on the power supply: Dial the band switch K to "battery voltage", and the battery voltage should be 0.7V.
3. Set the switch K to "polarization voltage", check whether the voltage added to both ends of the electrode is 0.7V (full scale of the meter head is 1V), low or high can be adjusted to "polarization fine-tuning" potentiometer.
4. switch K to "zero adjustment" gear, adjust the zero point of the amplifier, the meter pointer should be in the "0" point, if there is a deviation, adjust the "zero" potentiometer.
5. Switch K to 1/1 gear, electrode in the air, the meter head should indicate 21%, if any deviation can adjust the "sensitivity" potentiometer.
6. The electrode is inserted into the reaction bottle for measurement.