pH
IRI: https://spec.industrialontologies.org/ontology/construct/PH
Defined In: https://spec.industrialontologies.org/ontology/biopharma/BiopharmaMaterial/
SubClass Of: bfo:relational quality
Class Hierarchy
owl:Thing › bfo:entity › bfo:continuant › bfo:specifically dependent continuant › bfo:quality › bfo:relational quality › pH
Definition
quality of a material entity that is quantified as the negative decimal logarithm of the relative activity of hydrogen ions in that material entity
Explanatory Notes
pH is used in biopharmaceutical and laboratory practice as the standard indicator of how acidic or basic an aqueous material is. It is formally based on hydrogen-ion activity, often understood in aqueous systems through hydronium ion behavior, and is reported as a dimensionless value commonly near the 0–14 scale. In routine process and quality contexts, pH is treated as a practical measured attribute of buffers, culture media, process intermediates, and formulations. For heterogeneous materials, pH should be understood as referring to the relevant aqueous phase or sampled liquid portion, rather than to every part of the heterogeneous material.
Examples
- the pH of a phosphate-buffered saline solution measured as 7.4 at 25 °C; the pH of a chemically defined cell culture medium measured before inoculation; the pH of the aqueous phase of a mammalian cell culture during fed-batch cultivation;
Adapted From
- http://purl.obolibrary.org/obo/PATO_0001842 and http://purl.obolibrary.org/obo/NCIT_C45997
Primitive Class
This class is declared primitive and it does not have necessary and sufficient condiftions defined.
Primitive Rationale
This term is expected to remain primitive
Formal Axioms
First-Order Logic Axioms
PH(x) → RelationalQuality(x) ∧ ∃m (MaterialEntity(m) ∧ qualityOf(x, m))
Semi-Formal Natural Language Axioms
if x is ‘pH’ then x is a ‘relational quality’ that is the ‘quality of’ some ‘material entity’
Description Logic
constr:PH ⊑ bfo:relational_quality
constr:PH ⊑ ∃ constr:qualityOf .bfo:material_entity
constr:PH ⊓ constr:Osmolality ⊑ ⊥
constr:PH ⊓ constr:Osmolarity ⊑ ⊥
constr:PH ⊓ constr:Pressure ⊑ ⊥
SubClassOf: bfo:relational_quality
SubClassOf: constr:qualityOf some bfo:material_entity
constr:PH DisjointWith: (constr:Osmolality, constr:Osmolarity, constr:Pressure)