Skip to content

Sample pH

Notebook link where you can find all the graphs.

Data created on 17.10.2022 at 19:32:45

Data updated on 17.10.2022 at 19:32:45

Support by Ontologies

The definition of the pH is easily found in ontologies, the definition of Sample pH too. However, when users provide this value, it is not clear whether it really means the pH of the sample, the solvent, the solvent with the buffer, or another value. Due to the possible confusion, users tend to provide a detailed explanation within the solvent field as a free text, which unfortunately affects the machine-readability of both the solvent and the pH. You can find examples in the solvent page.

Data Sanitisation and Missing Values

It was possible to get the pH details only from MetaboLights.

Field TypeField NameValues ReadabilityUnitMissing
MTBLSdedicatedSample pHfree textnoneThe field is not provided; or the value is provided as N/A or other similar expressions; or the study "assays" value is "null"; or the value cannot be converted into a float.


It was possible to obtain the pH only from MTBLS, even though most of the studies didn't provide this metadata. Most samples' pHs were leaning towards the neutral 7, while a small percentage was around 4.

A rough estimate of the percentages of all studies in MTBLS repository based on the sample pH

Here one can see the number of studies providing the pH of the sample and its value.

The number of studies in MTBLS based on the sample pH