Laboratory tool

Peptide calculator

A volumetric converter for lyophilised material. Enter the content of the vial and the volume of solvent to get the concentration of the solution, then the volume corresponding to a mass you choose.

Concentration of the solution 2.50 mg/ml

Volume for the stated mass: 0.100 ml
On a U-100 syringe scale: 10.0 U
Measurements per vial: 20

A U-100 syringe has one hundred graduations to the millilitre, so one graduation is 0.01 ml whatever the vial contains.

Conversion tables

The concentration of the solution in milligrams per millilitre, for common vial sizes and solvent volumes. The values follow from dividing mass by volume and do not depend on which peptide is in the vial.

5 mg vial
Solvent	Concentration	100 µg is	250 µg is
1 ml	5.00 mg/ml	2.0 U	5.0 U
2 ml	2.50 mg/ml	4.0 U	10.0 U
3 ml	1.67 mg/ml	6.0 U	15.0 U
5 ml	1.00 mg/ml	10.0 U	25.0 U

10 mg vial
Solvent	Concentration	100 µg is	250 µg is
1 ml	10.00 mg/ml	1.0 U	2.5 U
2 ml	5.00 mg/ml	2.0 U	5.0 U
3 ml	3.33 mg/ml	3.0 U	7.5 U
5 ml	2.00 mg/ml	5.0 U	12.5 U

Frequently asked questions

How is the concentration of a reconstituted solution worked out?

Divide the mass in the vial by the volume of solvent added. A 5 mg vial reconstituted with 2 ml of solvent gives 2.5 mg/ml. Nothing about the peptide itself enters the calculation - the arithmetic is the same for any lyophilised material.

What does a graduation on a U-100 syringe correspond to?

A U-100 syringe carries one hundred graduations to the millilitre, so one graduation is 0.01 ml regardless of what the vial contains. The mass that volume represents depends entirely on the concentration you made.

Does the solvent volume change how much peptide is in the vial?

No. The vial contains what the certificate says it contains. Solvent volume changes the concentration of the solution and therefore the volume you measure out, not the quantity of material.