Ten Good Lab Practices When Testing for Dissolved Oxygen

When you measure how much oxygen is in dissolved water to test for water quality, you’ll want to follow some basic suggestions to maximize your efforts. The following tips will help you use your instruments properly and assess your readings correctly. For more information on testing dissolved oxygen, contact our Application Specialists.

1. To limit evaporation of the electrolyte solution, store your DO probe in a moist atmosphere
2. After each test, rinse probe membrane with distilled water
3. When you calibrate the probe and meter, make sure it is at temperatures closest to the sample temperature
4. Always ensure that the probe is submersed deep enough to cover the membrane and automatic temperature compensation element
5. For at least 15 cm/min, stir your sample to avoid oxygen starvation at the membrane
6. Calibrate your meter with a zero oxygen solution
7. Keep in mind that oxygen measurements are pressure- and altitude-dependent
8. Know your sample's salinity because it affects your reading
9. Allow 15 to 30 minutes to polarize polarographic probes
10. Remove all air bubbles from under the membrane surface when changing membranes