Magnesium sulfate (MgSO4) is soluble in water. Magnesium sulfate is available in anhydrous as well as hydrated forms. Since anhydrous Magnesium sulfate is highly hygroscopic (quickly absorbs water from the air), it is difficult to weigh it accurately, therefore, is not used for preparing solution. Magnesium sulfate heptahydrate (MgSO4·7H2O, Mol Wt: 246.47) is quite stable and often used for the preparation of 1M Magnesium sulfate solution.
A 1M stock solution can be prepared by dissolving 24.6.47 g of Magnesium sulfate heptahydrate (MgSO4.7H2O, Mol Wt: 246.47) in water to a final volume of 1000 ml.
Reagents and solutions
Magnesium sulfate (MgSO4.7H2O)
Deionized / Distilled water
Equipment and disposables
Conical flask / Beaker
1 M Magnesium sulfate
Preparation of 100 ml 1 M Magnesium sulfate
Step 1: To prepare 100 ml of 1 M Magnesium sulfate, weigh out 24.647 g Magnesium sulfate heptahydrate (MgSO4·7H2O, Mol Wt: 246.47) in a 250 ml conical flask/beaker. Add 800 ml deionized/Milli-Q water and mix until dissolved completely.
One can use manual shaking using a glass pipette to mix the ingredients. Magnetic stirrer makes the dissolving process easy and convenient.
Do not dissolve in 100 ml of deionized / Milli-Q water. In most cases, solution volume increases when a large amount of solute is dissolved in a solvent.
Step 2: Adjust the volume to 100 ml with deionized / Milli-Q water. Mix it again.
Step 3: Sterilize the solution by autoclaving (20 minutes at 15 lb/sq.in. (psi) from 121-124°C on liquid cycle).
The solution can also be sterilized by filtering it through a filter unit containing a membrane with a pore size of 0.22µm or less under sterile conditions.
The solution can be stored in the cold room.
|Follow the table to prepare Magnesium sulfate solution of various concentrations and volumes (100 ml, 500 ml, 1,000 ml, and 10,000 ml) from MgSO4·7H2O.|
|Solution concentration / Volume||10 ml||100 ml||500 ml||1000 ml|
|0.1 M||0.246 g||2.46 g||14.32 g||24.647 g|
|0.5 M||1.232 g||12.32 g||61.6175 g||123.235 g|
|1 M||2.464 g||24.64 g||123.235 g||246.47 g|
2 thoughts on “Preparation of 1M Magnesium Sulfate (MgSO4) Stock Solution”
In the table:
0.1 M 0.246 g 2.46 g 30.80 g (it should be 12.3)