Testing & Quality
Understanding Peptide Impurities
Learn about peptide-related impurities, degradation products and why different analytical methods may be needed to characterize a sample.
Estimated reading time:1minutes
“Purity” sounds like a single concept, but impurities can come from several different sources.
What is an impurity?
In analytical quality work, an impurity is a component other than the intended target material that is relevant to the particular analysis.
Where can peptide-related impurities come from?
Depending on the material and manufacturing process, peptide-related variants may include:
- Truncated or incomplete sequences
- Oxidized forms
- Deamidated or isomerized forms
- Other chemically modified forms
- Degradation products
Other non-peptide materials may also be relevant depending on manufacturing, purification and formulation.
Can one test detect every impurity?
Not necessarily.
Different analytical methods have different selectivity, sensitivity and detection characteristics.
A component that is poorly detected by one method may require another analytical approach.
Why does the analytical method matter?
A reported purity result is meaningful only in the context of the procedure that generated it.
Understanding the method, detector and calculation helps explain what the result actually represents.
Key Takeaway
Purity is method-dependent. A percentage should be interpreted alongside the analytical procedure and the types of impurities that procedure is capable of detecting.