Calculate the Peptide Content
The peptide content is the amount of pure peptide (Absolute weight) in a product and a lot specific value, because it depends on the purity and assay (content) of the lot.
The peptide calculator uses the analytical data which are documented in the respective Analytical data sheet (ADS) for Bachem’s products as shown in this example.
Please enter the values for purity (%), assay (%) and the weight (mg) of the sample and the Absolute weight will be calculated*.
BACHEM’S PEPTIDE CONTENT CALCULATOR
The following formula is used for the calculation of the Absolute weight:
Absolute weight = Gross weight × Purity × Assay
For the calculation of Volume, Concentration or Gross Weight, Purity and Assay are taken into consideration, unless the checkbox is set to “Use 100% for Purity and Assay.”
The calculation of the solvent volume is based on the following equation:
Volume = Absolute weight / (Concentration × Molecular weight) or Volume = (Gross weight × Purity × Assay) / (Concentration × Molecular weight) The result of this calculation is how much solvent is needed to dissolve a given quantity of lyophilizate to obtain a given concentration of pure peptide in solution.
The calculation of the concentration is based on the following equation:
Concentration = Absolute weight / (Volume × Molecular weight) or Concentration = (Gross weight × Purity × Assay) / (Volume × Molecular weight)
The result of this calculation is what the concentration of pure peptide in solution will be, if a given quantity of lyophilizate is dissolved in the given volume of solvent.
The calculation of the gross weight is based on the following equation:
Gross weight = (Volume × Concentration × Molecular weight) / (Purity × Assay)
The result of this calculation is how much lyophilizate is needed to obtain a given amount of a solution, which has a given concentration of the pure peptide.
Peptide purity is usually determined by reversed-phase HPLC and refers to the percentage of the target peptide compared to impurities that absorb at 220 nm (the peptide bond absorption wavelength). These impurities are often deletion sequences formed during synthesis.
Purity is critical for experimental accuracy, as lower purity (especially below 80%) can lead to greater lot-to-lot variability, compromising consistency and reliability in research or pharmaceutical applications.
How can this tool be used as a peptide dilution calculator?
Bachem’s peptide calculator helps you accurately prepare peptide solutions by determining how much solvent or peptide you need for a specific concentration. In this context, dilution means dissolving a given weight of peptide (factoring in purity and assay) into a volume of solvent.
By entering values like purity, assay, and sample weight, the calculator uses precise formulas to calculate net weight, solvent volume or final concentration, saving time and reducing errors.