Getting Started

Prepare the Probe

For a new dissolved oxygen probe, 0.5 mol/L NaOH solution should be added into the membrane cap first as the filling solution.

If the probe has been used for some time and the error grows greatly, it is time to change the filling solution.

The following tutorial details how to fill the probe with the NaOH solution.

• Unscrew the membrane cap from the probe and fill about 2/3 volume of the cap with 0.5 mol/L NaOH solution. Make sure the probe is in vertical position with respect to the horizontal plane. Carefully screw the cap back to the probe. It would be nice if a little bit solution overflows out of the cap to ensure the probe is fully filled with NaOH solution.

• When screwing the cap back to the probe, the probe should be in vertical position with respect to the horizontal plane to avoid creating bubbles in the filling solution.

• If the cap is fully filled with NaOH solution, there will be too much solution overflowing when screwing the cap back to the probe. If the filling solution is too little, bubbles may be created inside the cap. In sum, the best way is to fill about 2/3 volume of the cap. A little bit overflow when screwing the cap back to the probe is okay.

• Clean the overflowed solution with tissue.

• Screw the NaOH solution bottle after every use to prevent the CO2 in the air from affecting the solution.