Independent analytical testing. Results apply only to the sample received, for research use only.

Canada Peptide Testing
Request testing

Measurement basis and known limits

Compare testing methods.

Six techniques, each answering one question. This page states what every detector physically responds to, the checks a run has to pass before its results are reportable, and the blind spots that belong to the technique rather than to any particular sample.

See the panels these build
RP-HPLC-DAD · 220 nmArea purity 98.4%

Chromatogram: absorbance against retention time. The purity figure is the principal peak’s share of total integrated response, not its share of vial mass.

What the chromatogram can and cannot tell you

The chromatogram answers “how much of what I detected was the main component.” It does not answer “was that main component the molecule you told me to expect”. That is identity, and it is established separately by comparing the material against reference spectra. Neither answers “how many milligrams are in the vial”, which is a third measurement with its own calibration, run on request.

The chromatogram is reproduced on the certificate for the sample it came from, at the resolution needed to see the small resolved peaks rather than only the tall one.

See it on an example certificate

Method details

Each entry names the measurement principle, the detector basis, the suitability checks a run must pass, how the result is expressed, and what the technique cannot see no matter how carefully it is run.

HPLC-DAD

Reversed-phase high-performance liquid chromatography with diode-array detection

Answers: How much of the detected material is the principal component, and what else resolves alongside it under these conditions?

Measurement principle

The sample is dissolved and pushed through a non-polar stationary phase under a changing solvent gradient. Components partition between the mobile and stationary phases at different rates and therefore leave the column at different times. What the detector records is a trace of absorbance against retention time, and the area under each peak is proportional to how much of that component passed the detector.

Detection basis

Ultraviolet absorbance across the full diode-array range rather than at a single fixed wavelength. Purity is quantified near 220 nm, where the peptide bond itself absorbs, because that does not depend on the sequence containing an aromatic residue. The array records the whole spectrum of every peak at once, so the spectrum under one peak can be compared with the spectrum under another. Detection wavelength is printed on every chromatogram, because a purity figure without it is not interpretable.

System suitability before a result is reportable

  • Blank injection shows no interfering response in the region of the analyte
  • Replicate standard injections agree within the method acceptance criterion for area and retention
  • Principal peak resolution from the nearest resolved neighbour meets the method requirement
  • Peak asymmetry and plate count fall inside the range the method was established at
  • Baseline is stable enough for integration limits to be applied consistently across the run

Inherent blind spots

  • Anything that does not absorb at the detection wavelength is invisible: counter-ions, salts, residual solvent, and water contribute weight to the vial but no signal to the trace.
  • Two components that co-elute integrate as one peak, so a single clean-looking peak is a statement about resolution as much as about purity.
  • Area percent is normalised against what was detected, not against what was weighed, which is why it never functions as a strength or content figure.
  • Response factors differ between compounds, so an impurity area percentage is an estimate of its share of signal rather than of its share of mass.
  • Comparing spectra across a peak can show that the peak is not homogeneous, but matching spectra do not prove that it is: two compounds with similar chromophores can hide inside one peak.

How the result is reported

Area purity as a percentage of total integrated detected response, with the integration window, detection wavelength, gradient, column chemistry, and any excluded regions stated. Where a related substance is resolved and material, it is reported alongside rather than folded silently into the total.

HPLC Peptide Purity Testing
FTIR-ATR / Raman

Infrared and Raman vibrational spectroscopy against reference spectra

Answers: Does the received material produce the spectral pattern the expected compound produces, and does anything in the spectrum belong to something else?

Measurement principle

Molecular bonds absorb infrared light, and scatter laser light, at frequencies set by the masses of the atoms involved and the stiffness of the bonds between them. The pattern that results is characteristic of the functional groups present and of the backbone conformation they sit in. Infrared and Raman respond to different subsets of those vibrations, which is why the two are read together rather than one standing in for the other.

Detection basis

Infrared absorbance collected by attenuated total reflectance on the solid as received, and Raman scattering from the same material, each compared band by band against reference spectra for the expected compound.

System suitability before a result is reportable

  • A background collection immediately before the sample establishes what the instrument and the sampling accessory contribute
  • Signal-to-noise across the diagnostic region is sufficient for bands to be assigned rather than guessed at
  • The reference spectrum used for the comparison is identified and recorded with the result
  • Sampling contact or focus is confirmed, since a poor-contact spectrum flattens exactly the bands an assignment depends on

Inherent blind spots

  • Spectral matching is a comparison, not a sequence determination: peptides that share functional groups and backbone conformation can give closely similar spectra.
  • A minor component does not necessarily produce a band of its own, so these techniques confirm what dominates a sample far better than they find what is scarce in it.
  • The answer is only as good as the reference data available for that compound, which for newer research peptides can be thin.
  • Identity evidence says nothing about how much material is present, or whether it is safe.

How the result is reported

The techniques applied to the sample, the reference spectra they were compared against, the agreement observed, and the identity conclusion together with the limits placed on it.

Peptide Identity Testing
CE-UV

Capillary electrophoresis with ultraviolet detection

Answers: Does the sample behave as a single component under a separation that sorts by charge rather than by hydrophobicity, and is that consistent with the expected peptide?

Measurement principle

A voltage is applied across a narrow buffer-filled capillary, and components move through it at speeds set by their charge-to-size ratio rather than by how they partition into a stationary phase. Because the separation rests on a different physical property from chromatography, it can resolve what a reversed-phase column misses, and agreement between the two is worth more than either result alone.

Detection basis

Ultraviolet absorbance through the capillary window, recorded against migration time and compared with the behaviour of the expected compound under the same conditions.

System suitability before a result is reportable

  • Migration-time repeatability across replicate injections meets the method acceptance criterion
  • A blank run shows no interfering response in the migration window of interest
  • Buffer preparation and capillary conditioning follow the established method, since migration is sensitive to both
  • Current stays stable through the run, because a drifting current moves peaks without moving the compound

Inherent blind spots

  • Charge-to-size ratio is not identity: two different molecules can migrate together.
  • Migration times shift with buffer, temperature and capillary history, so comparisons hold only under matched conditions.
  • Species that ionise poorly, or absorb weakly, give little signal to work with.
  • Like every technique here, it describes the sample received and not the batch it came from.

How the result is reported

Migration behaviour and the resolved profile under the stated conditions, read alongside the chromatographic and spectroscopic results rather than as a standalone identity claim.

Peptide Identity Testing
Quantitative HPLC

Quantitative liquid chromatography against a calibrated reference standard, run on request

Answers: How much target peptide is actually in this vial, and how does that compare with the stated label claim?

Measurement principle

The same separation is run, but the analyte response is now compared against a calibration curve built from a reference standard of known concentration. Sample response is interpolated on that curve and back-calculated through the dilution scheme to a content figure for the vial as submitted.

Detection basis

The same ultraviolet response used for the purity separation, but treated as a quantitative signal calibrated against a standard rather than as a relative area. This work runs when it is asked for rather than on every sample, because it depends on a suitable reference standard being available for the compound.

System suitability before a result is reportable

  • Calibration curve meets the method requirement for linearity across the working range
  • Standards bracket the sample response, so the result is interpolated rather than extrapolated
  • A check standard analysed within the sequence recovers inside the method acceptance window
  • Replicate sample preparations agree within the method repeatability criterion

Inherent blind spots

  • The result can only be as good as the reference standard it is calibrated against, and for research-stage compounds a suitable standard is not always obtainable.
  • One vial is one vial. Content on a single unit says nothing about uniformity across a lot.
  • Salt form, counter-ion, and residual moisture all sit inside gross vial weight, which is the usual reason a content figure lands below a stated milligram fill even at high purity.
  • A content figure is a chemical measurement, not a potency or activity measurement, and does not convert to international units.

How the result is reported

Measured content in the agreed unit, the calculation basis, whether the figure is expressed as peptide base or as gross salt, the reference standard used, and the comparison against the nominal fill stated on the request.

Peptide Content and Label-Claim Testing
AAS / ICP-MS

Atomic absorption screening for elemental contaminants, with ICP-MS confirmation

Answers: How much lead, arsenic, cadmium, and mercury is in this material?

Measurement principle

The prepared sample is atomised, in a graphite furnace for the elements that need the lowest reporting limits and in a flame for the rest, and the free atoms produced absorb light at wavelengths characteristic of each element. Absorbance is proportional to how much of that element is present, without regard to what compound it was bound up in. Where the screen flags an element, the finding is confirmed by inductively coupled plasma mass spectrometry at a contract laboratory, which is named on the certificate.

Detection basis

Absorbance at the characteristic wavelength of each target element, converted to concentration against a calibrated elemental standard, with background correction applied so that the matrix is not read as analyte.

System suitability before a result is reportable

  • Calibration standards and a calibration blank bracket the reporting range for each element
  • A method blank is carried through the full preparation to establish the contribution of the process itself
  • Recovery of a spiked control stays inside the acceptance window across the sequence
  • A spiked recovery or reference material confirms the preparation is releasing the element from the matrix

Inherent blind spots

  • Only the elements in the accepted scope are measured. An element that was not on the list is not reported as absent, because it was never looked for.
  • The technique gives total elemental content and does not distinguish chemical species or oxidation state.
  • A screening result near its reporting limit is a reason to confirm by a second technique, not a final number on its own.
  • One vial is not a lot. Elemental contamination is often heterogeneous, so sampling drives how representative the number is.
  • Without an agreed specification there is no basis for calling a measured value a pass or a failure.

How the result is reported

A result per element, each with its own reporting limit and unit, expressed on the stated sample basis. Where a specification has been supplied and agreed, the comparison against it is stated; where none has, the measured value is reported without an implied pass.

Heavy Metals Testing
Kinetic LAL

Kinetic Limulus amoebocyte lysate assay for bacterial endotoxin

Answers: How much bacterial endotoxin does this preparation carry, against a stated reporting limit?

Measurement principle

Bacterial endotoxin triggers an enzymatic cascade in the lysate reagent. In the kinetic format, the time taken for the reaction to reach a defined threshold is measured and compared against a standard curve prepared from a reference endotoxin, so the answer comes from reaction onset time rather than from a visual endpoint.

Detection basis

Time to reach a defined optical threshold, interpolated against a standard curve built from control standard endotoxin at known concentrations.

System suitability before a result is reportable

  • Standard curve meets the correlation requirement across the concentration range used
  • Negative water control shows no reaction within the assay window
  • Positive product control recovers inside the accepted range, which is what demonstrates the sample is not inhibiting or enhancing the reaction
  • Dilution used stays at or below the maximum valid dilution for the stated limit

Inherent blind spots

  • A low endotoxin result is not sterility. The assay responds to a bacterial cell-wall component and does not detect viable organisms.
  • Some matrices interfere with the cascade in either direction, which is why the positive product control is reported rather than assumed.
  • The assay is specific to bacterial endotoxin and does not respond to other pyrogens.
  • Lysate is a biological reagent with lot-to-lot variation; where a request needs the animal-free alternative, recombinant factor C under the USP <86> framework is run in its place.
  • A pass requires an acceptance criterion, which has to be supplied or agreed in advance rather than invented by the laboratory.

How the result is reported

Endotoxin concentration in endotoxin units per millilitre or another agreed basis, with the reporting limit, dilution factor, and the outcome of the positive product control stated alongside it.

Bacterial Endotoxin Testing

Choosing a method

Methods are fit-for-purpose and operated under documented controls informed by ISO/IEC 17025 principles. Alignment with those principles is not accreditation, and this laboratory does not hold accreditation to that standard. Where a submission requires an accredited result for a regulatory purpose, say so at scope review and the request will be declined rather than accepted against the wrong expectation.

Method development, validation depth, and reference-material availability vary by analyte. The certificate for a given sample states the method that was actually run on it, and that statement governs, not this page.

How the quality system is run

Related guides

Quality system and data integrity Analytical glossary Sample requirements by matrix How to read a peptide COA

Ask about a sample

Contact the lab