When dealing with live brain tissue, low calcium/high magnesium artificial cerebrospinal fluid (low-cal) is needed to simulate the tissue's previous environment within an animal. Because cell recording cannot occur without this medium to keep the cell alive, low-cal is constantly used in neurophysiology laboratories. This instructable will walk you through the process of making 2 liters of 10x concentrated low-cal, or effectively 20 liters of standard low-cal.
Estimated time to completion: 15-25 minutes
- A balance or scale,
- A weigh boat or paper,
- A 2 liter volumetric flask,
- A stir plate and stir bar,
- A 2 liter storage container,
- Gloves (optional).
- Sodium chloride (NaCl)
- Potassium chloride (KCl)
- Magnesium chloride (MgCl2)
- Sodium phosphate monohydrate (NaH2PO4 * H2O)
- Calcium chloride dihydrate (CaCl2 * 2 H2O)
- Deionized water (H2O)
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Step 1: Mass Necessary Salts
Using the balance, obtain the following quantities of each salt and add to a 2 liter volumetric flask:
- NaCl - 121.56 g
- KCl - 7.01 g
- MgCl2 - 24.40 g
- NaH2PO4 * H2O - 3.26 g
- CaCl2 * 2 H2O -1.47 g
Step 2: Mix Solution Using Stir Plate
Fill the volumetric flask to the 2 liter mark with deionized water, then add the stir bar to the flask. Set the flask on the stir plate and adjust the stir setting the gently mix the solution.
Step 3: Store the Mixed Solution
After all the salts appear to have dissolved and the solution appears colorless throughout, pour the concentrated low-cal solution into your storage container. As long as the container is sealed properly, the low-cal solution will keep for 8-12 months.