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Peptide Testing Glossary

Definitions for 29+ terms used in peptide analysis, quality testing, and laboratory science

Last updated: February 2026

Accelerated Stability Testing

Stability

Stability studies at elevated temperature/humidity to predict shelf life within 3–6 months.

Bioburden

Contaminants

The count of viable microorganisms on a sample, measured before sterilization.

BPC-157

Peptide Types

Body Protection Compound-157, a 15-amino-acid research peptide studied for tissue repair.

Certificate of Analysis (COA)

Documentation

An official lab document reporting purity, identity, and quality results for a peptide batch.

cGMP

Standards

Current Good Manufacturing Practice — FDA regulations for pharmaceutical manufacturing.

Chromatogram

Documentation

A graph of detector response over time produced by HPLC analysis.

Deamidation

Degradation

A degradation pathway where Asn or Gln residues lose an amide group, shifting mass by +1 Da.

Deletion Sequence

Impurities

A peptide impurity missing one or more amino acids due to a failed coupling step.

Disulfide Bond

Chemistry

A covalent bond between two cysteines that stabilizes peptide 3D structure.

Endotoxin

Contaminants

Bacterial contaminants that cause fever and inflammation; tested via the LAL assay.

ESI-MS

Techniques

Electrospray Ionization Mass Spectrometry — a soft ionization method ideal for intact peptides.

GC-MS

Techniques

Gas Chromatography combined with Mass Spectrometry to detect residual solvents.

GLP-1 Receptor Agonist

Peptide Types

Peptides that activate GLP-1 receptors, used in metabolic and weight research (Semaglutide, Tirzepatide, Retatrutide).

Good Laboratory Practice (GLP)

Standards

A quality system for research labs ensuring data uniformity, reliability, and integrity.

HPLC

Techniques

High-Performance Liquid Chromatography — the gold-standard analytical method for measuring peptide purity.

ICH Guidelines

Standards

International standards for pharmaceutical method validation, stability, and impurity limits.

ICP-MS

Techniques

Inductively Coupled Plasma Mass Spectrometry — used to detect trace heavy metals at parts-per-billion sensitivity.

LC-MS/MS

Techniques

Liquid Chromatography combined with tandem Mass Spectrometry for both purity and identity in one run.

Lyophilization

Processes

Freeze-drying that produces stable peptide powder for shipping and long-term storage.

Mass Spectrometry (MS)

Techniques

An analytical method that measures mass-to-charge ratios to confirm peptide identity.

Method Validation

Standards

Demonstrating that an analytical method is accurate, precise, and fit for purpose per ICH Q2.

Oxidation

Degradation

A degradation pathway adding +16 Da, typically affecting methionine, cysteine, or tryptophan.

Peptide Aggregation

Degradation

Self-association of peptide molecules into oligomers or fibrils, reducing bioavailability.

Peptide Purity

Quality Metrics

The percentage of target peptide in a sample, measured by HPLC.

Post-Translational Modification (PTM)

Chemistry

Chemical changes to amino acids after synthesis, like phosphorylation or acetylation.

Shelf Life

Stability

How long a peptide retains specified purity and potency under recommended storage.

Solid-Phase Peptide Synthesis (SPPS)

Processes

The standard method for making synthetic peptides on a resin support.

TFA (Trifluoroacetic Acid)

Chemicals

A reagent used in peptide synthesis and purification; a frequently tested residual contaminant.

Truncated Peptide

Impurities

A shorter peptide fragment caused by incomplete synthesis or premature cleavage.

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