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Selection of Appropriate Peptide Purity
1.Is higher peptide purity always better?
Not necessarily. Higher purity increases cost, but not all experiments require ultra-high purity. Purity should be chosen according to the experimental purpose to balance experimental needs, reliability, and budget.
2.How is peptide purity determined?
Peptide purity is typically measured by reverse-phase high-performance liquid chromatography (RP-HPLC), detecting the proportion of the target peak area relative to the total peak area at 220 nm (the maximum absorption wavelength of the peptide bond).
Typical conditions: C18 column (4.6 × 250 mm, 5 μm, 100 Å), gradient elution (acetonitrile concentration increases ~1% per minute).
Results depend on column performance, gradient settings, and solvent selection, so slight variations may occur between laboratories.
3.Recommended minimum purity for different applications
Purity Level | Recommended Applications |
Crude (unpurified) | Mutation screening, sequence optimization, preliminary proteomics studies |
≥70% (Immunological grade) | ELISA, peptide microarrays, polyclonal antigen design, immunization, antiserum titer determination |
≥85% (Biochemical grade) | Western blot (non-quantitative), in vitro biological assays, epitope mapping, polyclonal development, cell adhesion studies, non-quantitative enzymatic assays |
≥95% (High purity) | Quantitative ELISA, RIA, receptor–ligand interaction studies (quantitative), in vivo and in vitro biological assays, NMR studies, quantitative enzymology, blocking experiments |
≥98% (Industrial/Pharmaceutical grade) | SAR studies, crystallography, GMP drug development, clinical research, reference standards preparation |
4.Why choose high purity?
More consistent results: Reduces batch-to-batch variation
Higher success rate: Minimizes interference from impurities and avoids repeat experiments
More reliable experiments: Suitable for quantitative and high-sensitivity studies
Higher safety: Essential for animal studies and clinical research
5.The salt form of a peptide, does it affect the experiment?
Most peptides are delivered as TFA salts, which may affect certain experiments. Alternative forms such as acetate or hydrochloride salts can be chosen according to experimental needs, but typically cost 20–30% more.
Aladdin: https://www.aladdinsci.com/