5 Questions on pH--Answered!
1. Can I measure the pH of a gas? How? The only way to measure the pH of a gas is this: dissolve it in distilled water and measure the mixture. Essentially, the pH of the distilled water/gas mixture will be that of the gas.
2. How should I store my electrode? The best option for short-term electrode storage is a prepared storage solution. Alternatives (in descending order) are: pH 4 buffer, pH 7 buffer, or tap water.
Never store your electrode in distilled/deionized water as it will leach out the electrolytes.
The best solution for long-term storage is to store the electrode dry and rehydrate it prior to use by soaking in a pH 4 buffer for a minimum of a half an hour. If it is a refillable electrode, empty the fill solution, then refill and hydrate it in pH 4 buffer for a minimum of half an hour.
3. When is a double-junction electrode better than a single-junction electrode? In dirty samples (those containing particulates, proteins, sulfides, and Tris buffers), a double-junction electrode is protected from becoming clogged through the second junction.
Single-junction electrodes should be considered primarily for use with clean water samples.
4. How do I unclog a pH electrode? To unclog a clogged junction, soak the electrode in a pH 4 buffer solution or KCl solution heated to 60 to 80°C for approximately 10 minutes. Allow it to cool in unheated solution, and then rinse with distilled water. If these steps do not restore the performance, replace the electrode.
5. How do I take soil pH measurements? Use our soil electrodes and prepare the sample by combining a 5-g soil sample with 5 g of distilled water, mixing thoroughly, and allowing the mixture to settle for 10 minutes. Carefully insert the probe so the bulb is in the soil part and the junction is in the supernatant. Allow the reading to stabilize. Follow this same procedure each time to produce consistent results.
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