pH Reference Poisoning – What You Need To Know
Because they can lead to reference poisoning, chlorides and sulfur-based compounds can have a major impact on pH sensors. When contaminants in the sample, such as chlorides or items containing sulphur, interact with the reference electrode and alter its voltage, reference poisoning happens. This may result in the sensor giving off erroneous data or perhaps causing the sensor to malfunction.
Typically, the reference electrode in a pH sensor is comprised of a metal in contact with a solution that has a known pH, such as silver or silver chloride. The sensor can detect the pH of the sample using the reference electrolyte, a solution that offers a steady voltage. A porous glass or ceramic junction that connects the reference electrode to the sensor enables ions to move between the reference electrolyte and the sample.
Chlorides or sulfur-based compounds can interact with the reference electrode and alter its voltage when they are present in the sample. For instance, chlorides can interact with the silver in the reference electrode to produce silver chloride, which can alter the reference electrode’s voltage. Similar to this, goods containing sulphur can interact with the reference electrode and alter its voltage. These reactions may result in erroneous voltage measurements from the reference electrode, which in turn may result in inaccurate pH readings from the sensor.
For sensors used in industrial or environmental applications, where samples may include significant quantities of chlorides or sulfur-based compounds, reference poisoning might be a particular difficulty. Using high-quality reference electrodes that are made to withstand reference poisoning in these circumstances is crucial, as is keeping them clean and maintained. To reduce the possibility of reference poisoning, it’s crucial to utilise a reference electrolyte that is compatible with the sample.
The negative impact of chlorides and sulfur-based compounds on pH sensors can also be reduced by employing pH sensors with built-in reference poisoning protection. These sensors may also have a protective coating that can aid to prevent reference poisoning. These sensors frequently employ a reference electrolyte that is less prone to react with chlorides or sulfur-based compounds.
In conclusion, chlorides and sulfur-based compounds can significantly affect pH sensors by reacting with the reference electrode and resulting in erroneous voltage readings. This may result in the sensor producing erroneous pH measurements or possibly in sensor failure. Use of high-quality reference electrodes, regular cleaning and maintenance, and the use of reference electrolytes compatible with the sample are all necessary to avoid reference poisoning.
