50-60% alcohol (methanol or ethanol), with the rest being water, along with a small amount of acids and bases – can this be measured with a pH meter?
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50-60% alcohol (methanol or ethanol), with the rest being water, along with a small amount of acids and bases – can this be measured with a pH meter?
What can it measure? A pH meter can certainly measure pH, but it can’t measure concentration
This post was last edited by qugd on 2022-6-21 at 10:15. The trend in the acidity or alkalinity of the measuring medium is fine, but the range of pH changes differs from that in aqueous media; therefore, comparative tests using similar media are necessary. In other words, the neutral point of acidity/alkalinity for your current medium is not necessarily 7 – it could be some other value away from 7, as the product of the ion concentrations of hydrogen ions and hydroxide ions in non-aqueous media is not 10-14, but some other value. Non-aqueous media have their own characteristics, and the trends observed in aqueous media serve only as a reference.
Potentiometric titration is recommended, unless you know exactly what type of acid and base it is.
Depending on actual needs, a pH meter can be used to measure acidity and alkalinity, or titration can be employed for this purpose. The former is rough, the latter is accurate.
It should be possible. Our sister unit deals with methanol and ethanol, which have concentrations ranging from 50% to 90%; the rest is water. The temperature is 65 degrees, and the pH level remains below 14. We use an online pH meter for this purpose
I agree with the opinions in post #4. Both methanol and ethanol are miscible with water. When a pH meter is used to measure the pH value of mixtures containing a high proportion of organic substances and water, along with small amounts of acids or bases, it can only provide a qualitative indication of whether the solution is acidic or alkaline; quantitative determination based on the measured pH value is not accurate. For water-containing mixture systems that are immiscible or only partially miscible, and provided that the pH meter is installed in the aqueous phase, the measured pH value is generally reliable.