Sodium Bicarbonate Buffer Calculator

Henderson-Hasselbalch Equation:

\[ pH = pKa + \log\left(\frac{[HCO_3^-]}{[H_2CO_3]}\right) \]

Calculated pH:

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1. What is the Sodium Bicarbonate Buffer System?

The sodium bicarbonate buffer system is a crucial physiological buffer that helps maintain blood pH within the normal range (7.35-7.45). It's the primary buffer system in extracellular fluid and is particularly important for neutralizing metabolic acids.

2. How Does the Calculator Work?

The calculator uses the Henderson-Hasselbalch equation:

\[ pH = pKa + \log\left(\frac{[HCO_3^-]}{[H_2CO_3]}\right) \]

Where:

\( pH \) — Negative logarithm of hydrogen ion concentration
\( pKa \) — Acid dissociation constant (6.35 for carbonic acid at 37°C)
\( [HCO_3^-] \) — Bicarbonate concentration (mol/L)
\( [H_2CO_3] \) — Carbonic acid concentration (mol/L)

Explanation: The equation describes the relationship between pH, pKa, and the ratio of bicarbonate to carbonic acid concentrations.

3. Importance of pH Calculation

Details: Accurate pH calculation is essential for understanding acid-base balance in biological systems, diagnosing acid-base disorders, and guiding therapeutic interventions.

4. Using the Calculator

Tips: Enter bicarbonate and carbonic acid concentrations in mol/L, and the pKa value (default is 6.35 for carbonic acid). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the normal ratio of bicarbonate to carbonic acid in blood?
A: The normal ratio is about 20:1 (bicarbonate:carbonic acid), which maintains blood pH at approximately 7.4.

Q2: Why is pKa 6.35 for this buffer system?
A: This is the acid dissociation constant for carbonic acid at physiological temperature (37°C). It represents the pH at which the acid is half dissociated.

Q3: How does this relate to respiratory and metabolic acidosis/alkalosis?
A: Changes in carbonic acid concentration primarily reflect respiratory disorders, while bicarbonate changes reflect metabolic disorders.

Q4: What are the limitations of this calculation?
A: It assumes ideal behavior and doesn't account for other buffer systems, temperature variations, or ionic strength effects.

Q5: How is this buffer system regulated in the body?
A: Through renal regulation of bicarbonate and respiratory regulation of carbon dioxide (which affects carbonic acid concentration).