Peptide Synthesizer Percent Yield Calculator

Calculator Inputs

Example Data Table

Formula Used

Scale from resin:

Scale mmol = Resin mass g × Resin loading mmol/g

Theoretical peptide mass:

Theoretical mass mg = Scale mmol × Molecular weight Da

Corrected actual peptide mass:

Corrected actual mg = Actual mg × Purity fraction × Assay fraction

Percent yield:

Percent yield = Corrected actual mg ÷ Theoretical mass mg × 100

Process model:

Adjusted expected mg = Theoretical mg × Coupling survival × Cleavage × Workup × Purification

The molecular weight can come from the sequence, a manual value, or an average residue estimate. The sequence method adds residue masses plus water for the peptide termini.

How to Use This Calculator

1. Enter the peptide sequence, or provide a manual molecular weight.
2. Add the recovered peptide mass from the final product.
3. Enter purity, moisture, and counter-ion corrections if known.
4. Provide resin mass and loading, or enter a manual scale.
5. Adjust coupling, cleavage, workup, and purification recoveries.
6. Press the calculate button to view results above the form.
7. Download the calculation as a CSV or PDF record.

Peptide Yield in Synthesis Workflows

Why Yield Matters

Percent yield is a practical mass balance value. It shows how much usable peptide was recovered from the planned synthesis scale. In peptide synthesis, the value is rarely controlled by one step only. Coupling efficiency, resin loading, cleavage, handling, drying, purification, and assay purity all affect the final number. A calculator helps convert these details into one consistent result.

Physics Behind the Mass Estimate

The calculation begins with amount of substance. Resin loading tells how many millimoles of growing peptide chains are present on each gram of resin. Multiplying resin mass by loading gives the reaction scale. Molecular weight then converts that mole amount into a theoretical mass. Since one millimole of a compound weighs the same number of milligrams as its molecular weight, the conversion stays simple.

Corrected Product Mass

A vial may not contain only pure peptide. Water, solvent, counter ions, salts, and side products can inflate the measured weight. This calculator corrects the recovered mass with purity and assay factors. That gives a better estimate of actual peptide content. The corrected mass is then compared with theoretical mass to produce percent yield.

Process Loss Interpretation

Step efficiency matters strongly for long sequences. A coupling efficiency of 99 percent looks high, yet repeated couplings compound the loss. Ten, twenty, or forty couplings can reduce the final amount before cleavage even begins. The adjusted process estimate combines coupling survival with cleavage, workup, and purification recovery. This helps compare expected yield against measured yield.

Better Batch Decisions

Use the result to compare syntheses, plan scale-up, and detect weak steps. A low corrected yield may indicate poor coupling, incomplete cleavage, product loss during purification, or inaccurate resin loading. A high performance against the adjusted estimate suggests that the synthesis behaved better than the selected process assumptions. Keep exported records with batch notes for trend analysis.

FAQs