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CJC-1295

What identity means for this molecule in numbers, how we measure its purity, and whether that method is validated yet. CAS none confirmed 863288-34-0, often printed for this peptide, is an associated number of CJC-1295 with DAC (C₁₆₅H₂₆₉N₄₇O₄₆, 3647.19 Da), whose registry number is 446262-90-4 (CAS Common Chemistry, FDA GSRS); the no-DAC peptide, Mod GRF (1-29), has no registry number we have confirmed.

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

C₁₅₂H₂₅₂N₄₄O₄₂

Monoisotopic mass

3365.8936 Da, free peptide

Average mass

3367.90 Da, free peptide

Expected charge states of CJC-1295 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+3H]³⁺	1122.9718	±0.0112	±11.2	0.334
[M+4H]⁴⁺	842.4807	±0.0084	±8.4	0.251
[M+5H]⁵⁺	674.1860	±0.0067	±6.7	0.201
[M+6H]⁶⁺	561.9895	±0.0056	±5.6	0.167

Scan range 300–2200. The bold state is the one expected to be most abundant. We expect the envelope to centre on the smaller of M/1000 + 1 and the larger of the basic-site count and M/1000, M in daltons; here that is M/1000 + 1 = 4.4. It has 6 basic sites, and a peptide this size rarely carries more charges than that. A molecule this size spreads across several states, and every state we record, at least the two most abundant, has to agree.

The last column is the spacing between neighbouring isotope peaks of each ion: the mean step one heavy isotope adds to this composition, 1.0029 Da, divided by the charge. The higher the charge, the closer the peaks; at [M+6H]⁶⁺ they sit 0.167 m/z apart, one part in 3 400 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+.

What the mass cannot see. This peptide differs from an isomer of identical mass only in the D-alanine at position 2 (the L-Ala2 epimer is isobaric). Mass spectrometry cannot see that difference; with Purity, the retention time of the main peak against our reference standard, printed with the system suitability, is the only evidence the report offers for it, and an identity-only report has none.

Before you send. A sample of the DAC form (C₁₆₅H₂₆₉N₄₇O₄₆, 3645.0155 Da monoisotopic) is identified against its own formula, not this one; tell us which you have, and ask before you ship the DAC form, since it is not a row of this table.

Expected envelope · computed The charge states a 3.4 kDa 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 (+0.984 Da) is sought on any sequence with asparagine or glutamine. The sequence has them; where it applies it is confirmed on the chromatogram as a closely eluting peak, before or after the parent, since at charge z the mass shift is 0.984/z m/z, which at 4+ and above overlaps the M+1 isotope.
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 CJC-1295

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.