Calculator

Buffer pH Calculator

Advanced Buffer pH Calculator

Complete Buffer Analysis & Preparation Tool

🧪 Buffer Solutions

Mixtures of weak acids/bases with their conjugate pairs that resist pH changes upon addition of acids or bases.

📐 Henderson-Hasselbalch

pH = pKa + log([A⁻]/[HA]) for acidic buffers. Essential equation for buffer calculations and design.

⚡ Buffer Capacity

Maximum buffering occurs when pH = pKa. Effective range is typically pKa ± 1 pH unit.

Select Calculation Mode:

Calculate Buffer pH

Enter Ka in scientific notation or decimal form
Alternative: Enter pKa directly (pKa = -log₁₀(Ka))
Concentration of the weak acid component
Concentration of the conjugate base (salt form)
Temperature affects equilibrium constants (default 25°C)

📚 Common Laboratory Buffer Systems

🔬 Standard Buffer Recipes (1L, 0.1M)

💡 Buffer Preparation Best Practices

Choose Appropriate pKa

Select a buffer with pKa within ±1 pH unit of your target. Buffering capacity is maximum when pH = pKa.

Temperature Considerations

Tris: -0.028 pH/°C, Phosphate: -0.003 pH/°C, HEPES: -0.014 pH/°C. Adjust pH at working temperature.

Ionic Strength Effects

High salt concentrations affect pH. Add salts before final pH adjustment or use ionic strength corrections.

Avoid Metal Chelators

Phosphate and citrate chelate metal ions. Use Good's buffers (HEPES, MES, MOPS) for metal-sensitive work.

Concentration Guidelines

10-100 mM for most applications. Higher concentrations increase capacity but may affect osmolarity and ionic strength.

Sterilization Methods

Autoclave phosphate/Tris buffers. Filter-sterilize biological buffers (HEPES, MES) to prevent degradation.

Storage Stability

Store at 4°C. Check pH before use. Some buffers support microbial growth - add sodium azide (0.02%) if needed.

CO₂ Sensitivity

Tris and bicarbonate buffers are CO₂-sensitive. Keep covered. HEPES resists CO₂ interference - ideal for cell culture.

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