Current clamp · K-gluconate
Current-clamp internal solution recipe
A 50 mL K-gluconate internal solution starting recipe for whole-cell current-clamp and action-potential recordings. Use the interactive calculator to scale the batch or edit individual ingredients.
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50 mL starting recipe
| Compound | Final (mM) | MW (g/mol) | Source | Add |
|---|---|---|---|---|
| K-gluconate | 128.0 | 234.3 | Powder | 1499.2 mg |
| KCl | 10.0 | 74.6 | Powder | 37.3 mg |
| HEPES | 10.0 | 238.3 | 100.0 mM stock | 5000.0 µL |
| EGTA | 1.0 | 380.4 | 100.0 mM stock | 500.0 µL |
| MgCl₂ | 1.0 | 203.3 | 1000.0 mM stock | 50.0 µL |
| CaCl₂ | 0.3 | 111.0 | 1000.0 mM stock | 15.0 µL |
| Na₂ATP | 5.0 | 507.2 | Powder | 126.8 mg |
| NaGTP | 0.3 | 523.2 | Powder | 7.8 mg |
Why this internal?
K-gluconate-based internal solutions are commonly used for current-clamp recordings when the goal is to preserve a potassium-dominant intracellular environment while measuring membrane potential and action-potential firing. The built-in recipe is a starting formulation, not a universal standard.
Current-clamp behavior depends on the complete internal and external ionic composition, electrode properties, liquid junction potential, pH, and osmolality.
How the amounts are calculated
Powder
mg = mM × mL × MW ÷ 1000
Stock solution
µL = desired mM × final mL × 1000 ÷ stock mM
Before preparing the solution
Treat this as a starting formulation. Verify the exact salt form, hydration state, molecular weight, and assay on each supplier label. Adjust pH experimentally, bring the mixture to final volume, and measure osmolality. The nominal concentration sum is not an osmolality prediction.