Third-Party Peptide Testing: HPLC & Mass Spec Explained
Understanding independent laboratory testing is essential for quality research. Learn how HPLC purity analysis and mass spectrometry verification ensure you're working with genuine, high-purity peptides.
Third-party testing is the gold standard for peptide quality verification. When an independent laboratory—with no financial connection to the manufacturer—analyzes a peptide, the results are objective and unbiased. This testing typically includes HPLC purity analysis and mass spectrometry identity confirmation.
This guide explains how these testing methods work, what the results mean, and why independent verification is critical for valid research outcomes.
Why Third-Party Testing Matters
The difference between in-house and third-party testing is objectivity. While manufacturers may have excellent internal QC, there's an inherent conflict of interest when a company tests its own products.
Eliminates Bias
Independent labs have no financial incentive to produce favorable results. Their reputation depends on accurate, honest reporting.
Traceable Documentation
Third-party COAs include lab accreditation info, analyst signatures, and timestamps—creating an auditable quality record.
Research Validity
Publishing research requires confidence in your materials. Third-party verification provides the documentation peer reviewers expect.
Consistency Assurance
Batch-to-batch testing ensures each lot meets specifications, critical for reproducible experimental results.
HPLC Purity Analysis
What is HPLC?
High-Performance Liquid Chromatography (HPLC) is the industry standard for measuring peptide purity. The technique separates a sample's components based on their chemical properties, then quantifies each component.
How It Works:
- 1. Sample Injection: A small amount of dissolved peptide enters the HPLC system
- 2. Separation: The sample flows through a column packed with specialized material
- 3. Detection: Different compounds exit at different times, detected by UV/light absorption
- 4. Analysis: Software calculates the percentage of each peak in the chromatogram
Understanding HPLC Results
| Purity Level | Research Grade | Typical Use |
|---|---|---|
| >99% | Premium | Publication-quality research |
| 98-99% | High | Standard research applications |
| 95-98% | Standard | Preliminary studies, screening |
| <95% | Low | Not recommended for research |
- Main Peak: Should be >99% of total area for premium grade peptides
- Retention Time: Should match the expected time for that specific peptide
- Peak Shape: Clean, symmetrical peaks indicate good separation and sample quality
Mass Spectrometry Identity Verification
What is Mass Spectrometry?
While HPLC tells you how pure a sample is, mass spectrometry (MS) tells you what it actually is. MS measures the molecular weight of compounds with extreme precision, confirming the peptide's identity.
Common MS Types
- • ESI-MS (Electrospray Ionization)
- • MALDI-TOF
- • LC-MS (combined with HPLC)
What MS Confirms
- • Correct molecular weight
- • Peptide identity verification
- • Detection of modifications
Reading MS Results
Theoretical Mass
The calculated molecular weight based on the peptide's amino acid sequence. This is what you expect to see.
Observed Mass
The actual mass measured by the instrument. Should be within ±1 Da (Dalton) of theoretical mass.
Mass Tolerance
A difference of ±0.1% is typical for high-quality MS. Larger discrepancies may indicate incorrect product or significant impurities.
Signs of Quality Third-Party Testing
Green Flags
- • Named, accredited testing laboratory (ISO 17025)
- • Unique batch/lot number matching your product
- • Full chromatogram image included
- • Both HPLC and MS results on the same COA
- • Analyst signature and test date
- • Lab contact information verifiable online
Red Flags
- • Generic COA without specific lot number
- • No laboratory identification
- • Missing chromatogram or spectrum images
- • Round numbers only (exactly 99.0%, not 99.23%)
- • No date or very old testing date
- • Unable to verify lab exists
BioInfinity Lab Testing Standards
Every peptide sold by BioInfinity Lab undergoes independent third-party testing:
- HPLC Purity Testing: Minimum ≥99% purity requirement for all products
- Mass Spectrometry: Identity verification on every batch
- Batch-Specific COAs: Every lot tested individually, not by "representative sample"
- Public COA Library: All certificates available for download
Frequently Asked Questions
What is third-party peptide testing?
Independent laboratory analysis by a facility with no financial connection to the manufacturer, providing objective verification of purity and identity.
What does HPLC testing measure?
HPLC measures peptide purity by separating components and calculating the percentage of target peptide versus impurities. Results show purity as a percentage.
What does mass spectrometry confirm?
MS verifies peptide identity by measuring molecular weight. The observed mass should match the theoretical mass for the claimed peptide.
What purity should I look for?
For publication-quality research, ≥99% purity is recommended. Standard research typically uses ≥98%. Below 95% is not recommended.
How can I verify a COA is legitimate?
Look for named, verifiable laboratories, unique batch numbers, actual chromatogram images, and contact information you can cross-reference online.