Glossary

Predetermined specifications that a product batch must meet to be considered acceptable. For peptides, this typically includes minimum purity thresholds (e.g., purity ≥ 95%), identity confirmation, and appearance standards. A COA should state these criteria alongside actual results.

The specific order of amino acids that make up a peptide. Written using single-letter or three-letter codes (e.g., H-Gly-His-Lys-OH). The sequence defines the peptide's identity and is a critical item on any COA.

A unique identifier assigned to a specific production run. Allows traceability from raw materials through manufacturing to final testing. Every COA should reference a batch number so results can be traced to a specific set of vials.

A formal document issued by a laboratory reporting quality test results for a specific product batch. For peptides, a COA typically includes identity confirmation, purity data, impurity profiles, and batch traceability information. It is the primary quality communication tool between manufacturer and buyer.

A visual graph produced during chromatographic analysis (e.g., HPLC). Shows peaks representing separated compounds in a sample, plotted as detector response over time. The main peak represents the target peptide; smaller peaks represent impurities. Peak height, area, shape, and retention time all carry analytical meaning.

A documented trail tracking the handling and transfer of a sample from collection to analysis. Ensures the sample tested is the same one collected and has not been tampered with. Critical for independent verification credibility.

A common peptide impurity where one or more amino acids are missing from the intended sequence. Created during solid-phase synthesis when a coupling step fails. Detected via HPLC as secondary peaks and confirmed by mass spectrometry.

A system of quality standards and guidelines for manufacturing and laboratory processes. Covers everything from facility design and equipment maintenance to documentation and personnel training. GMP compliance ensures consistent, reproducible quality.

An HPLC technique where the composition of the mobile phase changes over time during analysis. Gradually increasing the organic solvent concentration allows better separation of complex peptide mixtures. The gradient profile should be documented on a comprehensive COA.

The primary analytical technique for measuring peptide purity. A sample is dissolved, injected into a column packed with stationary phase material, and separated by a flowing mobile phase. Different compounds move through the column at different rates, allowing quantification. The result is a chromatogram showing purity and impurity profiles.

A characterization of all impurities detected in a sample — their identity (if known), relative quantity, and origin. Includes deletion sequences, truncated peptides, oxidation products, and residual solvents. A thorough COA reports impurity data alongside the main purity figure.

International Organization for Standardization certification confirming a laboratory or facility meets specific quality management standards. ISO 17025 applies to testing laboratories; ISO 9001 to quality management systems. Accreditation adds credibility to a COA.

An analytical method for determining water content in a sample. Important for peptides because water content affects stability, accurate weighing, and dosing calculations. Results are typically expressed as a percentage. Sometimes listed on COAs as "water content" or "moisture."

A technique combining HPLC separation with mass spectrometry detection. Provides both purity data (from LC) and identity confirmation (from MS) in a single analysis. Considered the gold standard for peptide characterization.

A preservation process where water is removed from a frozen product by sublimation under vacuum. Most research peptides are supplied as lyophilized powder for stability. The appearance of the lyophilized product (white powder, intact cake) may be noted on a COA.

An analytical technique that measures the mass-to-charge ratio of ions. For peptides, it confirms molecular identity by verifying the observed molecular weight matches the calculated weight. Essential for distinguishing the target peptide from impurities that may co-elute on HPLC.

The liquid solvent mixture that carries the sample through an HPLC column. Typically a combination of water and an organic solvent like acetonitrile, often with a small amount of acid (e.g., TFA). The mobile phase composition affects separation and should be documented on a COA.

The total mass of a molecule, calculated from its atomic composition. For peptides, expressed in Daltons (Da) or g/mol. The COA should show both the calculated (theoretical) molecular weight and the observed (measured) weight from mass spectrometry. Close agreement confirms identity.

The actual amount of active peptide in a vial, accounting for salt content, water, and counterions. A vial labeled "5 mg" may contain 5 mg of gross weight but only 3.5-4.5 mg of actual peptide. Net peptide content is important for accurate research dosing and should be specified on a COA.

The proportion of the target compound relative to all detected substances in a sample, expressed as a percentage. A purity of 98.5% means 98.5% of detected material is the target peptide, with 1.5% being impurities. Measured by HPLC based on chromatographic peak area.

A short chain of amino acids linked by peptide bonds. Typically 2-50 amino acids in length (longer chains are called proteins). Research peptides are synthesized for scientific study and include compounds like BPC-157, TB-500, and various growth hormone secretagogues.

A testing methodology where samples are selected from a batch without the manufacturer's control or knowledge of which units will be tested. Prevents cherry-picking of favorable samples. A cornerstone of independent verification at GMP Analytics.

The time it takes for a compound to travel through an HPLC column and reach the detector, measured from injection to peak maximum. Each compound has a characteristic retention time under specific conditions. Used to help identify compounds and ensure consistent analysis.

The most common method for manufacturing research peptides. Amino acids are added one at a time to a growing chain attached to a solid resin. After the sequence is complete, the peptide is cleaved from the resin and purified. Impurities arise from incomplete couplings, side reactions, and cleavage byproducts.

The material packed inside an HPLC column that interacts with sample compounds to cause separation. For peptide analysis, C18 (octadecyl) columns are most common. The column type affects separation quality and should be documented on a COA.

A common counterion and mobile phase additive in peptide chemistry. Most synthetic peptides are supplied as TFA salts. TFA content is sometimes reported on COAs and can affect peptide weight and biological activity in research applications.

A peptide impurity that is shorter than the intended sequence, typically resulting from premature termination during synthesis. Detected as secondary peaks in HPLC and confirmed by mass spectrometry showing a lower-than-expected molecular weight.