TY - JOUR
T1 - Acid content and buffer-capacity
T2 - a charge-balance perspective
AU - Ring, Troels
AU - Rees, Stephen Edward
AU - Frische, Sebastian
PY - 2022/9
Y1 - 2022/9
N2 - Rational treatment and thorough diagnostic classification of acid-base disorders requires quantitative understanding of the mechanisms that generate and dissipate loads of acid and base. A natural precondition for this tallying is the ability to quantify the acid content in any specified fluid. Physical chemistry defines the pH-dependent charge on any buffer species, and also on strong ions on which, by definition, the charge is pH-invariant. Based, then, on the requirement of electroneutrality and conservation of mass, it was shown in 1914 that pH can be calculated and understood on the basis of the chemical composition of any fluid. Herein we first show that this specification for [H+] of the charge-balance model directly delivers the pH-dependent buffer-capacity as defined in the literature. Next, we show how the notion of acid transport as proposed in experimental physiology can be understood as a change in strong ion difference, ΔSID. Finally, based on Brønsted-Lowry theory we demonstrate that by defining the acid content as titratable acidity, this is equal to SIDref - SID, where SIDref is SID at pH 7.4. Thereby, any chemical situation is represented as a curve in a novel diagram with titratable acidity = SIDref - SID as a function of pH. For any specification of buffer chemistry, therefore, the change in acid content in the fluid is path invariant. Since constituents of SID and titratable acidity are additive, we thereby, based on first principles, have defined a new framework for modeling acid balance across a cell, a whole organ, or the whole-body.
AB - Rational treatment and thorough diagnostic classification of acid-base disorders requires quantitative understanding of the mechanisms that generate and dissipate loads of acid and base. A natural precondition for this tallying is the ability to quantify the acid content in any specified fluid. Physical chemistry defines the pH-dependent charge on any buffer species, and also on strong ions on which, by definition, the charge is pH-invariant. Based, then, on the requirement of electroneutrality and conservation of mass, it was shown in 1914 that pH can be calculated and understood on the basis of the chemical composition of any fluid. Herein we first show that this specification for [H+] of the charge-balance model directly delivers the pH-dependent buffer-capacity as defined in the literature. Next, we show how the notion of acid transport as proposed in experimental physiology can be understood as a change in strong ion difference, ΔSID. Finally, based on Brønsted-Lowry theory we demonstrate that by defining the acid content as titratable acidity, this is equal to SIDref - SID, where SIDref is SID at pH 7.4. Thereby, any chemical situation is represented as a curve in a novel diagram with titratable acidity = SIDref - SID as a function of pH. For any specification of buffer chemistry, therefore, the change in acid content in the fluid is path invariant. Since constituents of SID and titratable acidity are additive, we thereby, based on first principles, have defined a new framework for modeling acid balance across a cell, a whole organ, or the whole-body.
KW - Electrochemistry
KW - acid-base disorders
KW - acid-base equilibrium
KW - biological water-electrolyte balance
KW - buffers
KW - chemistry
KW - computer simulation; models
KW - physical mathematics physical chemistry ions
KW - Humans
KW - Ions
KW - Sudden Infant Death
KW - Acid-Base Equilibrium/physiology
KW - Hydrogen-Ion Concentration
UR - http://www.scopus.com/inward/record.url?scp=85133531116&partnerID=8YFLogxK
U2 - 10.1080/00365513.2022.2092903
DO - 10.1080/00365513.2022.2092903
M3 - Journal article
C2 - 35792720
SN - 0036-5513
VL - 82
SP - 356
EP - 362
JO - Scandinavian Journal of Clinical and Laboratory Investigation
JF - Scandinavian Journal of Clinical and Laboratory Investigation
IS - 5
ER -