Precautions for testing samples with pH test paper?

1. The pH test paper can only detect liquids, but it cannot be tested after wetting it with water, otherwise the test results will be biased.
2. Do not put the pH test paper into the liquid to be tested to avoid polluting the entire sample. You can use a clean glass rod or other clean tools to take part of the sample to be tested, and observe the results when the sample is dropped on the pH test paper.
3. The color displayed on the test paper can be observed in real time, and the observation may be affected by other factors after staying for too long, resulting in inaccurate results.