Reference
Peptide & Analytical Testing Glossary
Plain definitions for the terms used across our product pages, Certificates of Analysis, and research articles — peptide chemistry, chromatographic and mass-spectrometric methods, compendial standards, and batch documentation vocabulary.
Peptide Science
Core vocabulary used to describe peptide identity, structure, and formulation in research-use materials.
Peptide
- A short chain of amino acids joined by peptide bonds. Peptides are typically defined as chains shorter than proteins, and are described by their primary amino acid sequence, molecular formula, and molecular weight.
Amino Acid Sequence
- The ordered list of amino acid residues in a peptide, conventionally written from the N-terminus to the C-terminus. Sequence integrity is the primary identity attribute confirmed during analytical release testing.
Molecular Weight (MW)
- The mass of one mole of a compound, expressed in daltons or g/mol. For peptides, the observed molecular weight is compared against the theoretical value calculated from the sequence to confirm identity.
Solid-Phase Peptide Synthesis (SPPS)
- A synthesis method in which a peptide chain is assembled residue by residue while anchored to an insoluble resin support, then cleaved and purified. SPPS is the standard route for producing research-use peptides.
Lyophilisation
- Freeze-drying: removal of solvent from a frozen solution by sublimation under vacuum, producing a dry powder or cake. Lyophilised peptides are reconstituted with a suitable diluent before use in laboratory work.
Reconstitution
- The laboratory step of dissolving a lyophilised compound in a defined volume of diluent to produce a solution of known concentration for in-vitro work.
Bacteriostatic Water
- Sterile water containing 0.9% benzyl alcohol as a bacteriostatic preservative, allowing multiple withdrawals from a single vial in laboratory workflows.
Research Use Only (RUO)
- A supply designation indicating that a material is intended exclusively for in-vitro laboratory research and analytical testing, and is not evaluated or approved for human or veterinary use, diagnosis, or therapy.
Analytical Methods
Instrumental techniques used to verify the identity, purity, and composition of peptide reagents.
High-Performance Liquid Chromatography (HPLC)
- A separation technique in which a sample is carried by a pressurised liquid mobile phase through a packed column, resolving components by their differing interactions with the stationary phase. Peak areas are used to estimate relative purity.
Reversed-Phase HPLC (RP-HPLC)
- The most common HPLC mode for peptides, using a non-polar stationary phase (typically C18) with a polar aqueous-organic gradient. Purity is normally reported as the main peak area as a percentage of total integrated peak area.
Mass Spectrometry (MS)
- An analytical technique that ionises a sample and separates the ions by mass-to-charge ratio, producing an observed molecular mass that is compared against the theoretical mass of the intended sequence to confirm identity.
Liquid Chromatography–Mass Spectrometry (LC-MS)
- A hyphenated technique that couples chromatographic separation with mass detection, allowing both purity assessment and mass confirmation of the resolved peak in a single run.
Purity
- The proportion of a sample attributable to the intended compound, most commonly reported for peptides as chromatographic area percent by RP-HPLC at a specified detection wavelength.
Purity Threshold
- The minimum purity a batch must meet to be released, stated as a specification such as ≥ 98.0% or ≥ 99.0% by RP-HPLC. Vector E Lab publishes the applicable threshold on each product page.
Impurity
- Any component of a batch other than the intended compound, including synthesis-related species, residual solvents, and degradation products. Impurity profiles are assessed chromatographically.
Residual Solvent
- Volatile organic solvent remaining in a material after synthesis and purification. Residual solvents are classified and limited by recognised compendial and ICH frameworks.
Standards & Compendial References
Published frameworks referenced across the analytical literature. These entries define the standards themselves; they are not statements that any given batch was tested to a particular chapter.
United States Pharmacopeia (USP)
- A compendium of public standards for the identity, strength, quality, and purity of medicines, excipients, and related materials in the United States, organised into numbered general chapters.
USP <61>
- The USP general chapter covering microbiological examination of non-sterile products: microbial enumeration tests, including total aerobic microbial count and total combined yeasts and moulds count.
USP <62>
- The USP general chapter covering microbiological examination of non-sterile products: tests for specified micro-organisms, used alongside the enumeration tests of USP <61>.
USP <71>
- The USP general chapter describing sterility tests, defining the procedures and acceptance criteria used to demonstrate the absence of viable micro-organisms in materials labelled sterile.
USP <621>
- The USP general chapter on chromatography, defining system suitability parameters — such as resolution, tailing factor, repeatability, and theoretical plates — used to judge whether a chromatographic method is performing acceptably.
USP <233>
- The USP general chapter describing procedures for the determination of elemental impurities, typically by ICP-OES or ICP-MS.
USP <467>
- The USP general chapter covering residual solvents, defining solvent classes and concentration limits together with gas chromatographic procedures for their determination.
ICH Q2
- The International Council for Harmonisation guideline on validation of analytical procedures, defining characteristics such as specificity, linearity, range, accuracy, precision, and quantitation limit.
ICH Q3C
- The ICH guideline on residual solvents, establishing solvent classification and permitted daily exposure concepts that underpin compendial residual-solvent limits.
ICH Q1A
- The ICH guideline on stability testing, describing storage conditions and study designs used to establish how a material's quality attributes change over time.
Certificate of Analysis Terms
Terminology used on batch documentation and in the Vector E Lab COA library.
Certificate of Analysis (COA)
- A document issued for a specific batch that records the tests performed, the methods used, the results obtained, and the release specification against which those results were judged.
Batch
- A defined quantity of material produced in a single run under uniform conditions, identified by a unique batch number so that documentation and results can be traced to the exact material supplied.
Lot-Specific Documentation
- Analytical documentation tied to one identified lot or batch rather than to a product line in general, allowing a laboratory to match the certificate to the vial in hand.
Traceability
- The ability to follow a material from the supplied unit back through its batch number to the corresponding production and analytical records.
Specification
- The set of acceptance criteria a batch must meet for release, expressed as tests, analytical procedures, and numerical limits or descriptive criteria.
Testing Date
- The date on which the reported analytical testing was performed for a batch, recorded on the certificate so results can be placed in time relative to storage and use.
Strength
- The declared quantity of compound per unit — for peptide vials, typically the nominal mass of lyophilised material, expressed in milligrams.
Third-Party Testing
- Analysis performed by a laboratory independent of the supplier, providing an external check on identity and purity results.
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Definitions are provided for reference only. Listing a standard does not assert that a given batch was tested to that chapter; batch testing is recorded on the applicable Certificate of Analysis.