Dissolved oxygen measurement interference involves which instrument/conditions?

Dissolved oxygen measurement interference involves which instrument/conditions?

• A. Pressure fluctuations
• B. Membrane/optical probe: algae and oils
• C. Temperature changes
• D. Salinity changes

Answer: (B)

Dissolved oxygen measurement interference happens when something alters the sensor’s response without reflecting the true oxygen level. For membrane-based and optical DO sensors, the sensing path or window has to stay clean for accurate readings. Algae growth or oils can coat or foul the membrane or the optical surface, creating a barrier to oxygen diffusion or to light transmission. That fouling changes how the sensor responds, often biasing readings or slowing response times, even if the actual dissolved oxygen in the water is different. In short, algae and oils directly disrupt the sensor interface, making them a prime source of interference. Temperature, pressure, and salinity can affect DO concentration or sensor calibration, but they don’t interfere with the sensor interface in the same direct, fouling way as algae and oils.

Dissolved oxygen measurement interference happens when something alters the sensor’s response without reflecting the true oxygen level. For membrane-based and optical DO sensors, the sensing path or window has to stay clean for accurate readings. Algae growth or oils can coat or foul the membrane or the optical surface, creating a barrier to oxygen diffusion or to light transmission. That fouling changes how the sensor responds, often biasing readings or slowing response times, even if the actual dissolved oxygen in the water is different. In short, algae and oils directly disrupt the sensor interface, making them a prime source of interference. Temperature, pressure, and salinity can affect DO concentration or sensor calibration, but they don’t interfere with the sensor interface in the same direct, fouling way as algae and oils.