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NAMED CAPABILITY · PEPTIDE ANALYSIS
NAMED CAPABILITY

Peptide analysis

A peptide arrives as a white powder with a certificate, and the certificate usually says less than it appears to. We run the analysis ourselves, on our own HPLC, and tell you what is actually in the vial.

We run it in our lab

We have an HPLC with a diode array detector on site at Fitzsimons, and we run analytical samples on it ourselves. The person who runs the method is the person who reads the chromatogram and writes to you about it.

  • Purity by reversed-phase HPLC. Run at 214 nanometers, which sees the amide backbone and therefore every peptide-related impurity, rather than at 280, which only sees aromatic residues and will miss an impurity that has none.
  • Peak purity by diode array. Collecting the full spectrum across each peak shows whether a single peak is one species or two that co-elute. A purity figure from a single wavelength cannot tell the difference, and a co-eluting impurity is exactly the one a supplier gradient was tuned to hide.
  • Gradient development. A steep gradient co-elutes close impurities into the main peak and inflates the purity figure. We develop a gradient that resolves what is there and then hold it constant across every lot you send.
  • Lot-to-lot comparison. The same method across lots, which is the only way a purity number means anything as a comparison.
  • Stability-indicating work. Forced degradation and time-course runs under the conditions you actually store and use the material in.
  • Quantitation against a reference. Where you supply or we establish a standard.

What we report

A chromatogram, the method that produced it, and a written read of what it means for your material. Where a result is ambiguous we say so rather than rounding it into a number.

The questions this answers

  • Is the purity on the supplier certificate reproducible on an honest gradient.
  • Has this lot changed against the one that worked.
  • Is the material degrading in your storage buffer, and how fast.
  • Are the two lots from two suppliers the same thing.

Beyond the HPLC

Some questions cannot be answered by chromatography, and we will tell you which ones rather than stretching the method past what it supports.

  • Identity needs mass spectrometry. Retention time matching against a reference is supporting evidence, not confirmation, and a diode array spectrum narrows it without settling it.
  • Peptide content, the fraction of the powder that is peptide rather than counterion and water, needs amino acid analysis or nitrogen determination. It is the number that most often makes a potency result wrong, and it is usually missing from a research-grade certificate.
  • Disulfide connectivity in a peptide with more than two cysteines needs proteolytic mapping, because every regioisomer has the same mass.
  • Bioburden and endotoxin are separate specified tests. Neither is implied by a purity figure.

We bring LC-MS in on rental when a question needs it, so identity and mass confirmation can run alongside the chromatography rather than going out to a third party. For the rest we scope the test, say who should run it, and interpret the result as part of the same piece of work.