Is Your Henderson–Hasselbalch Calculation of Buffer pH Correct? (Journal Article)
Lucy, Charles A.
Is Your Henderson–Hasselbalch Calculation of Buffer pH Correct? (Journal Article) - Washington DC :American Chemical Society ,2023 - 2418-2422p. - Journal of Chemical Society , Volume 100: Number 6, June 2023 .
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Abstract: A survey of 21 free online buffer calculators and apps found only 2 that correctly calculated pH under conditions where [H+] and [OH–] cannot be ignored in the ratio term of the Henderson–Hasselbalch equation. Traditional guidelines for when use of formal concentrations is acceptable were found to be flawed. For acidic (pKa ≤ 7) buffers, the use of formal concentrations is valid when FA–/Ka > 20. For alkaline (pKa ≥ 7) buffers, the approximation is valid when FBH+/Kb > 20. Robust equations for predicting pH of acidic and alkaline buffers are presented, which could be used with programmable calculators and should be used for online buffer calculators and apps.
0021-9584
Buffers| Acid−Base Chemistry| Analytical Chemistry| General Chemistry
Is Your Henderson–Hasselbalch Calculation of Buffer pH Correct? (Journal Article) - Washington DC :American Chemical Society ,2023 - 2418-2422p. - Journal of Chemical Society , Volume 100: Number 6, June 2023 .
***______________***
Abstract: A survey of 21 free online buffer calculators and apps found only 2 that correctly calculated pH under conditions where [H+] and [OH–] cannot be ignored in the ratio term of the Henderson–Hasselbalch equation. Traditional guidelines for when use of formal concentrations is acceptable were found to be flawed. For acidic (pKa ≤ 7) buffers, the use of formal concentrations is valid when FA–/Ka > 20. For alkaline (pKa ≥ 7) buffers, the approximation is valid when FBH+/Kb > 20. Robust equations for predicting pH of acidic and alkaline buffers are presented, which could be used with programmable calculators and should be used for online buffer calculators and apps.
0021-9584
Buffers| Acid−Base Chemistry| Analytical Chemistry| General Chemistry