Lab Transparency

Our Commitment to Quality

At ChinaPeptideshop, transparency is not a marketing claim—it is the foundation of our business. Every product ships with its supplier’s batch specification, and we send selected lots to Janoshik Analytical for independent testing. We do not run these tests in-house. We believe researchers deserve visibility into the quality of the materials they use, which is why the reports we publish link to the original on Janoshik’s own portal.

HPLC Purity Testing

High-Performance Liquid Chromatography (HPLC) is the gold standard for assessing peptide purity. A typical method uses a reverse-phase C18 column with UV detection at 214 nm to separate and quantify the molecular species in a peptide sample.

How HPLC Works

• Sample preparation: The sample is dissolved in a standardized solvent system (water/acetonitrile with 0.1% TFA)
• Column separation: Components are separated based on hydrophobicity using gradient elution
• UV detection: The peptide bond absorbs strongly at 214 nm, providing sensitive detection of all peptide species
• Area integration: Purity is calculated as the percentage of the main peak area relative to total peak area
• Reporting: The report states the purity result; many labs include the chromatogram

Each product’s supplier batch specification states its purity standard. A Janoshik report shows the purity measured on the lot it tested.

Mass Spectrometry Verification

While HPLC confirms purity, mass spectrometry confirms identity. Electrospray ionization mass spectrometry (ESI-MS) checks that the molecular weight of a sample matches the theoretical value calculated from the amino acid sequence.

Together, the two methods answer “how pure?” and “is it the right molecule?” for the lot that was tested.

What a COA Can Contain

A certificate of analysis can document the fields below. Every product ships with its supplier’s batch specification; for the lots we send to Janoshik, the report shows the measured purity, identity and content.

Field	Description
Product Name	Full peptide name and catalog number
Lot Number	Unique batch identifier for traceability
Sequence	Complete amino acid sequence
HPLC Purity	Percentage purity with chromatogram
Mass Spec (MS)	Observed vs. expected molecular weight
Appearance	Physical description (lyophilized white powder)
Net Content	Peptide mass per vial
Storage	Recommended storage conditions
Date	Analysis date and analyst authorization

How to Read a COA

• Check the purity: Look for the HPLC purity percentage. For quantitative research, you want ≥98%, ideally ≥99%
• Verify identity: Compare the observed molecular weight to the expected value. They should match within ±0.1% (typically ±1 Da)
• Review the chromatogram: A single dominant peak with a flat baseline indicates high purity. Multiple significant peaks suggest impurities
• Check the lot number: Ensure it matches the label on your vial for traceability
• Note the date: Testing should be recent relative to your purchase date