What is the most common type of probe used in a DO meter?

The most common type of probe used in a dissolved oxygen (DO) meter is the membrane electrode. This type of probe functions by utilizing an electrochemical reaction to measure the concentration of dissolved oxygen in water. The membrane electrode typically consists of a sensing membrane that allows oxygen to pass through while keeping other substances out, facilitating a measurement that is both accurate and reliable.

When the probe comes into contact with water, oxygen diffuses through the membrane and reaches the electrode surface. At the electrode, an electrochemical reaction occurs, generating a current that is proportional to the amount of oxygen present. This current is then converted into a DO concentration reading. The design of the membrane electrode makes it suitable for a wide range of applications in wastewater analysis, including both lab settings and field measurements.

Other types of probes, such as the optical probe, detect dissolved oxygen through fluorescence quenching but are less commonly used compared to membrane electrodes, particularly in traditional settings. Similarly, a platinum probe is often associated with specific applications outside of standard DO measurements, and a screw-type probe is not a recognized category within DO meters because it does not align with common measurement technology. Thus, the membrane electrode is widely acknowledged as the standard tool for assessing dissolved oxygen levels in various aquatic environments.