Determination of ethylene glycol acidity
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The national standard specifies a method for determining the acidity of ethylene glycol, which is by titration. However, there are limitations on the concentration. The concentration of ethylene glycol we are using at present is 48%, and there are some scale inhibitors in it; using titration, the color change is not obvious, making it difficult to determine the endpoint. What about using a pH meter? We are currently using ordinary pH electrodes, and the measurement results are very unstable. After consulting some suppliers, they mentioned that there are specialized pH electrode testers available. I wonder if anyone has used them and what the results were like. Please share your insights!
An unclear endpoint in acid-base titrations is likely related to the presence of impurities; if the pH meter functions accurately during other acid-base titrations, this issue may persist even after using a dedicated electrode. I wonder if it is related to the slow release of hydrogen ions from the impurities?
What about diluting the sample before titration?
Or use an automatic analyzer, without an indicator.