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GHK

What identity means for this molecule in numbers, how we measure its purity, and whether that method is validated yet. CAS 49557-75-7 Not yet checked against the CAS registry. The free tripeptide GHK; the copper complex is 89030-95-5, also not yet checked against the CAS registry.

Identity by mass spectrometry

Identity by LC–MS means every charge state we record lands within 10 parts per million of where the formula says it must. That establishes the formula of the main component; the limits page says what it does not establish. The windows below are that criterion in daltons, at each m/z.

Molecular formula

C₁₄H₂₄N₆O₄

Monoisotopic mass

340.1859 Da, free peptide

Average mass

340.38 Da, free peptide

GHK tripeptide; the copper complex is C₁₄H₂₂N₆O₄Cu. LC–MS reports the free peptide. This method confirms the GHK tripeptide and reports its purity. It does not determine whether copper is present or how much: in the acidic mobile phase the complex dissociates and the mass spectrum is that of the free peptide. A vial of GHK and a vial of GHK-Cu give the same identity result here. We do not measure copper. [M+2H]²⁺ at m/z 171.1002, often the stronger GHK ion, is below the scan floor; a scan from m/z 150 would record it.

Expected charge states of GHK in the scan range, with the 10 ppm identity window at each and the spacing of its isotope peaks.
State	m/z	10 ppm, Da	10 ppm, mDa	Isotope spacing, m/z
[M+H]⁺	341.1932	±0.0034	±3.4	1.003

Scan range 300–2200. Only [M+H]⁺ falls inside it; [M+2H]²⁺, at m/z 171.10, is below the floor, so identity rests on that single ion. One ion within 10 ppm fixes the mass of one species; it cannot show charge states agreeing with each other, and it cannot tell this peptide from an isomer of the same formula or from another species at the same m/z, which only the retention time against our reference standard, with Purity, speaks to.

The last column is the spacing between neighbouring isotope peaks of each ion: the mean step one heavy isotope adds to this composition, 1.0026 Da, divided by the charge. The higher the charge, the closer the peaks; at [M+H]⁺ they sit 1.003 m/z apart, one part in 340 of its m/z. Resolving power is m/z over the smallest separation an instrument shows, so the method’s floor of 10 000 at m/z 1000 shows peaks 0.1 m/z apart there, against 0.20 m/z between the isotope peaks of a 5+ ion at that m/z: that is why the 10 ppm criterion is applied only on an instrument of that resolving power or better, and why a unit-resolution instrument, which shows peaks about 1 m/z apart, cannot pick the monoisotopic peak out of any cluster past 1+.

Expected envelope · computed The charge states a 340 Da peptide should present in ESI+, placed by arithmetic from the formula. Relative intensities are a model. Nothing here is a measurement; the measured spectrum appears on the report.

Method and validation status

Purity is area percent by RP-HPLC–UV 214 nm. Identity is LC–MS (ESI+). The matrix we accept is lyophilised powder.

Status

Validation: Not yet validated
Retention time: not yet measured on this analyte
Limit of quantitation: not yet measured
Reporting threshold: 0.05% area; no limit of quantitation is claimed yet, so a smaller peak may be present and not seen

Not yet validated means the method is written and has not been run on this analyte. The retention time and the limit of quantitation are listed once measured, with the date of the validation that produced them. The scope table shows the status of every analyte.

What the formula tells us to watch for

Deamidation does not apply: the sequence has no asparagine or glutamine.
Truncation products - the sequence short by one or more residues - fall at characteristic mass offsets and are looked for at their expected m/z where the sequence is on file; the certificate lists the impurity masses that were read and whether each was assigned.

Order a test of GHK

Identity and purity together, $185, in 10 business days or the invoice is cancelled, or the payment refunded, and you still get the results. One sealed container as received.

Order a test How to send a sample

What you get back

A certificate with the chromatogram, every peak, the three injections, the measured spectrum against the windows above, what could not be resolved, a full signature, a hash and a QR that verifies without us. How to read one.