Reconstitution Calculator
Free Reconstitution Calculator for mixtures & solutions. Enter variables to compute results with formulas and detailed steps.
Reviewed by Manoj Kumar, Mathematics Educator
Formula
Volume = (mass / molar mass) / desired concentration
Calculate the moles of compound available from the mass and molar mass, then divide by the desired molar concentration to find the volume of solvent needed. The result gives the total volume of solution to prepare.
Worked Examples
Example 1: Peptide Reconstitution
Problem:You have 5 mg of a peptide (MW = 1200 g/mol). How much solvent is needed for a 10 mM stock solution?
Solution:Moles = 5 mg / 1000 / 1200 g/mol = 0.000004167 mol\nVolume = 0.000004167 / 0.01 M = 0.0004167 L\nVolume = 0.4167 mL = 416.7 uL
Result:Add 416.7 uL of solvent
Example 2: Drug Reconstitution
Problem:Dissolve 50 mg of a drug (MW = 350 g/mol) to make a 100 mM solution.
Solution:Moles = 50 / 1000 / 350 = 0.0001429 mol\nVolume = 0.0001429 / 0.1 = 0.001429 L\nVolume = 1.429 mL
Result:Add 1.429 mL of solvent
Frequently Asked Questions
What is reconstitution in chemistry?
Reconstitution is the process of dissolving a dry or lyophilized (freeze-dried) substance back into a liquid solvent to create a solution of a specific concentration. This is commonly done with peptides, proteins, antibodies, and pharmaceutical compounds that are stored in powder form for stability. The key calculation involves determining how much solvent to add to achieve the desired concentration based on the mass of the powder and its molecular weight.
How do you calculate the volume needed for reconstitution?
First, calculate the number of moles of substance you have by dividing the mass (in grams) by the molar mass. Then divide the number of moles by the desired concentration (in mol/L) to get the volume of solvent needed in liters. For example, if you have 5 mg of a compound with a molar mass of 500 g/mol and want a 10 mM solution, you have 0.00001 mol. Dividing by 0.01 mol/L gives 0.001 L or 1 mL of solvent needed.
What solvents are commonly used for reconstitution?
The choice of solvent depends on the compound being dissolved. Water or sterile saline is used for water-soluble compounds. DMSO (dimethyl sulfoxide) is commonly used for hydrophobic compounds and small molecules in research. Ethanol or methanol can be used for moderately hydrophobic substances. For proteins and peptides, buffered solutions like PBS (phosphate buffered saline) are preferred to maintain biological activity. Always check the compound datasheet for recommended reconstitution solvents.
References
Reviewed by Manoj Kumar, Mathematics Educator · Editorial policy