ShopLaboratory test kitsSAVE 10%Research method overviewInstrumentsLab accountsFAQ
Shop by category
Bench Instruments8HPLC & Chromatography10Mass Spec Prep4Endotoxin & Growth-Detection Supplies7Quantitation & UV3Pipetting & Handling5Laboratory Test Kits11
Help
Contact support
Research method overview

Laboratory methods used in peptide research

An overview of six analytical workflows, the limited question each can address, and the equipment typically required. This is product-selection information, not a validated method, release specification, diagnostic procedure, or safety determination.

IdentityPurityContentEndotoxinSterilityQuick screen
01 · Mass spectrometry

Identity: does the observed mass agree with the expected molecular mass?

Mass spectrometry can support an identity assessment by comparing an observed molecular mass with the theoretical mass. An intact-mass agreement alone does not prove sequence, structure, purity, or suitability for any use. Validated acceptance criteria and orthogonal methods may be required.

  1. Desalt the sample on a C18 tip
  2. Mix with matrix (MALDI) or dilute in the mobile phase your method specifies (LC-MS)
  3. Acquire and compare the observed mass with the theoretical mass
In-house? Requires a suitable mass spectrometer and a qualified method. We sell only selected sample-preparation supplies; the laboratory or contract facility is responsible for the analysis and interpretation.
02 · Reversed-phase HPLC

Purity: what chromatographic area profile does the defined method produce?

Reversed-phase HPLC separates UV-absorbing components under a defined chromatographic method. Relative peak area is method-specific and is not an absolute identity, purity, or content determination.

  1. Prepare and filter the mobile phases your method specifies, then degas them
  2. Dissolve the sample and filter it into a vial
  3. Run the gradient and integrate the peaks
In-house? Requires an HPLC system, appropriate detector, reference materials where applicable, system-suitability criteria, and a qualified method. We sell selected columns and consumables — not the HPLC system, and not solvents or acid modifiers.
03 · Weighing, BCA and UV

Content: what concentration estimate does the selected method produce?

Gravimetric weight measures total material, not peptide alone. BCA and UV response depend on sequence, matrix, standard, wavelength, and method. Quantitative claims require appropriate calibration and validation.

  1. Equilibrate the vial in a desiccator, then weigh with static neutralised
  2. Dissolve to a known volume
  3. Read against a standard curve by BCA (562 nm) or UV (205–220 nm)
In-house? These measurements may be performed by a suitably equipped research laboratory. The laboratory is responsible for calibration, controls, method suitability, and interpretation.
04 · LAL gel-clot

Endotoxin: does a validated lal method detect endotoxin at the stated threshold?

A gel-clot LAL method can detect endotoxin at or above the assay's stated sensitivity under validated conditions. Sample interference, dilution, positive-product controls, reagent lot qualification, and acceptance criteria must be addressed. A result does not by itself establish safety or suitability for release or administration.

  1. Dilute the sample in LAL reagent water in depyrogenated tubes, using endotoxin-free tips
  2. Add lysate; run the positive product control from your lysate vendor and a water negative control
  3. Incubate 60 min at 37 °C, then invert and read
In-house? Use only in a qualified laboratory following the manufacturer's instructions and a validated, sample-appropriate method. The products listed here do not by themselves constitute a validated release test.
05 · Culture in two media

Sterility: does a qualified culture method detect growth under the stated conditions?

A qualified culture method can detect microbial growth under its defined conditions. A no-growth result does not by itself prove sterility or suitability for release or administration. Facility controls, aseptic technique, method suitability, incubation controls, and validated acceptance criteria are required.

  1. Work aseptically in a clean hood
  2. Filter the sample or inoculate the media directly
  3. Incubate 14 days and check for turbidity
In-house? Requires qualified aseptic facilities, trained personnel, appropriate controls, and a validated method. The incubator and media sold here are not sufficient on their own to perform a compendial release test.
06 · Thin-layer chromatography

Quick screen: does the sample show an unexpected tlc pattern?

TLC can flag gross differences or unexpected spots under a defined comparison. It cannot establish identity, purity, content, safety, or suitability for any use.

  1. Spot the sample and a reference side by side
  2. Develop in a saturated chamber using the solvent system your method specifies
  3. Dry, then view under 254 nm
In-house? Performed in a research laboratory with a UV lamp. The comparison is qualitative and depends on the reference material, solvent system and conditions you choose. Developing solvents and stains are not supplied.
Not sure where to start?

Tell us what you're testing.

Tell us the workflow, instrument model and method requirements, and we will suggest suitable products. We do not provide a validated method.

Ask a questionBrowse kits