Measuring pH on metallic planar surface

AI Thread Summary
Measuring pH levels on the wet surface of metals is crucial for corrosion studies, especially when a non-conductive protective layer is present. The feasibility of measuring pH on planar surfaces, whether dry or wet, is confirmed, and selecting the right sensor probe is essential for accurate readings. Precision is a key concern, and the order of magnitude for measurements will depend on the sensor used. A suggested method involves using an indicator in conjunction with a spectrophotometer, which can provide reliable results. Recommendations for suitable indicators are needed, particularly those that can endure prolonged use over years. The choice of indicator will ultimately depend on the specific pH range relevant to the study. Further insights on the expected pH range will aid in selecting the most appropriate indicator.
Patrick Rota
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We are currently trying to measure pH levels on the (wet) surface of metals as part of a study about corrosion.
The surface may have a non-conductive protective layer.

- is it feasible to measure pH on a planar surface (dry or wet)? Which kind of sensor probe can be used for this task?
- which order of magnitude will be the measure? (precision of the sensor)

Any advice would be greatly appreciated!
 
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My first thought would be to use and indicator in combination with a spectrophotometer.
 
Thank you DrDu, this is a great idea, indeed.
Can you recommend some indicator? Do you have suggestions?
EDIT: we need an indicator for prolonged use (years), if it exists
 
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The choice of the indicator will depend on the pH range you are interested in.
 
Dear DrDu, thank you for your insight. Let me find out what is the pH forecast range.
 
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