Dissolved oxygen analyzerThe operation steps are as follows:

Preparation before use

Electrode polarization: If the instrument has not been used for a long time, the electrode should be connected to the host and polarized for 20-30 minutes to ensure the stability of the sensor.

Probe inspection:

Check if the probe film is intact, without damage or aging;

Confirm that the metal electrode is tightly attached to the film and free from rust, and if necessary, use fine sandpaper to polish it;

Check if the electrolyte inside the probe is sufficient. If there are bubbles, replace the electrolyte with a new one (it is recommended to use the original electrolyte).

Reagent preparation: Prepare reagents according to calibration requirements, such as 5% freshly prepared sodium sulfite solution (zero oxygen calibration solution), deionized water, etc.

Water sample collection:

Collect water samples using a clean and odorless sampler to avoid contamination;

It is recommended to collect at a location close to 50cm underwater to ensure the representativeness of the water sample;

If there is a significant difference between the temperature of the water sample and room temperature, it should be allowed to stand until the temperature stabilizes before measurement.

instrument calibration

Zero oxygen calibration:

Immerse the electrode in zero oxygen calibration solution (5% sodium sulfite solution) and gently stir;

After the reading is stable, adjust the zero adjustment knob or relevant settings to make the instrument display 0.

Full oxygen calibration:

Clean the electrode and dry it with filter paper;

Place the electrode close to the surface of a conical flask containing deionized water (without contact with water) and wait for the reading to stabilize;

Adjust the span calibration knob or related settings to indicate the saturated dissolved oxygen value of pure water at this temperature.

Attention: The calibration steps for different models of instruments may vary slightly, and specific operations should refer to the instructions.

　　Dissolved oxygen analyzerMeasurement operation

Electrode insertion: Immerse the electrode into the water sample to be tested, ensuring sufficient contact with the water sample.

Mixing water sample:

Gently stir the water sample with a mixer or manually, keeping the probe always in the water sample;

To avoid measurement errors caused by oxygen consumption near the probe.

Wait for stability: According to the measurement principle of the instrument, wait for 5-10 minutes (or the instrument prompts a stable reading) before reading the data.

Read data:

Record the dissolved oxygen concentration value displayed by the instrument (unit: mg/L);

Simultaneously record information such as measurement date, time, and water sample temperature for subsequent analysis.

Post use maintenance

Electrode cleaning:

After use, rinse the electrode with deionized water to remove any residual water sample;

Avoid wiping the electrodes with hard objects to prevent damage to the film.

Electrode storage:

Short term idle: immerse the electrode in deionized water to keep the probe moist;

Long term idle: Separate the probe from the host and store the electrodes in a dry environment.

Instrument shutdown: Turn off the power of the instrument and remove the battery (if not used for a long time) to avoid battery leakage and damage to the instrument.

Regular calibration: It is recommended to calibrate the instrument every 10 days to ensure measurement accuracy; If the instrument is used frequently, the calibration cycle can be shortened.

Consumables replacement: Regularly replace consumables such as electrolytes and probe films, with specific cycles determined by usage frequency and manufacturer recommendations.