Preparation of 1M Calcium chloride (CaCl2) Stock Solution

OVERVIEW

  • Calcium chloride is a salt of calcium and chlorine. 
  • Calcium chloride is available commercially in both anhydrous (CaCl2) and hydrated forms (CaCl2 H2O, CaCl2 2H2O, CaCl2 4H2O, CaCl2 6H2O). Any of them can be used to prepare 1 M calcium chloride stock solution. 
  • Anhydrous calcium chloride is solid white powder at room temperature. It is highly hygroscopic, therefore, it must be kept in tightly sealed, air-tight containers. 
  • Anhydrous calcium chloride and the lower hydrates emit a large amount of heat when dissolved in water (exothermic reaction). Care should be taken while dissolving them in water. 
  • Anhydrous CaCl2 is difficult to weigh accurately as it is highly hygroscopic (quickly absorbs water molecules from air). In this regard, Calcium chloride dihydrate and tetrahydrate are relatively more stable and major form at room temperature (Karunadasa et al., 2018), and are suitable to prepare stock solutions.
  • A 1 M calcium chloride solution can be prepared by dissolving 147.02 g of CaCl2.2H2O in water to a final volume of 1000 ml. 

REQUIREMENTS

Reagents and solutions
Calcium Chloride Dihydrate (CaCl2.2H2O; Molecular weight = 147.02)
Deionized water

Equipment and disposables
Measuring cylinder
Conical flask / Beaker
Magnetic stirrer

Composition
1M Calcium Chloride

PROCEDURE

Step 1: To prepare 1000 ml of 1 M calcium chloride (CaCl2) solution, weigh out 147.02 g of CaCl2.2H2O (Molecular weight: 147.02) and dissolve in 800 ml deionized / Milli-Q water using magnetic stirrer.

Tip:
◊ One can use manual shaking using a glass pipette to mix all ingredients. Mixing using a Magnetic stirrer is optional. The magnetic stirrer makes the dissolving process easy and convenient.

Precautions:
◊ Do not dissolve in 1000 ml of deionized / Milli-Q water. It is always a good practice to dissolve all media ingredients first and then adjust the volume to the desired volume with the solvent. In most cases, solution volume increases when a large amount of solute dissolves in the solvent.

◊ Make sure to dissolve any residual powder sticking to the glass.

Step 2: Adjust the volume to 1000 ml with deionized water. Mix it again.

Step 3: Transfer the medium to an autoclavable bottle. Sterilize the solution by autoclaving (20 minutes at 15 lb/sq.in. (psi) from 121-124°C on liquid cycle).

Storage
The solution can be stored at room temperature or in a cold room.

Follow the table to prepare the calcium chloride solution of various concentrations and volumes from CaCl2.2H2O.
Conc. / Volume100 ml250 ml500 ml1000 ml
10 mM0.15 g0.37 g0.73 g1.47 g
50 mM0.73 g1.84 g3.67 g7.35 g
100 mM1.47 g3.67 g7.35 g14.70 g
0.5 M7.35 g18.37 g36.75 g73.50 g
1 M14.7 g36.75 g73.50 g147.00 g 

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