VIP (vasoactive intestinal peptide) certificate of analysis, field by field
Updated 2026-10-05 · 1 certificate ·
Issued by AxisPharm, LLC · Laboratory documentation · Research use only
PepsMartUSA publishes one certificate of analysis for VIP (vasoactive intestinal peptide), the
28-residue peptide, covering the 10 mg vial. It was issued by AxisPharm, LLC, the testing laboratory our
supplier, Protixa, sends samples to, and Protixa provided it to us. Below: every field the certificate prints, how to
read the multiply charged ions of a peptide this size, why its printed molecular weight is one unit above the figure
on our product page, and what it doesn't report.
Issued by AxisPharm, LLC, provided by our supplier, Protixa. Identity for every lot was by LC-MS;
the detected masses are under identity below.
The certificate, field by field
The fields below are copied from the PDF as printed, including any that disagree with each other.
VIP 10mg · Lot VIP10VAS0426
Laboratory (From)
AxisPharm, LLC
Addressed to (To)
Protixa
Brand name
Protixa
Certificate ID
30Apr2026-03
Report date
April 30, 2026
Sample received
04/23/2026 · lab activity 04/29/2026
Condition on receipt
Acceptable
Sample name
Vasoactive Intestinal Peptide (VIP), 10mg
Method(s)
LCMS and LAL Endotoxin Assay
Label claim
10 mg
Net weight measured
10.2 mg
Molecular weight
3326.8 g/mol
Detected
1664.7 [M+2H], 1109.8 [M+3H]
UV purity
>99.3% at 208 nm
Endotoxin (LAL)
0.061 EU/mg
MFD / BBD
04/2026 / 04/2028
Storage on receipt
-20°C
Traces reproduced
UV chromatogram (TWC) and mass spectrum
Molecular weight. The printed 3326.8 g/mol is one unit above the 3325.8 for amidated
VIP on our product page; see identity.
Lot number in a different typeface. The lot number, VIP10VAS0426, is
printed in a sans-serif typeface, unlike the text around it, as on other AxisPharm reports in our library from
April to June 2026. The PDF's own data record one creation, by Microsoft Print to PDF on April 30, 2026, the report
date, and no later revision, so the lot number was printed that way when the file was made.
Molecular weight is for native VIP, which ends in an amide (Sigma-Aldrich, Cayman). The certificate prints 3326.8 g/mol, the figure PubChem gives for a structure ending in a free acid; its detected ions fit either form.
Sequence
HSDAVFTDNYTRLRKQMAVKKYLNSILN
Reference identity data are cross-checked against PubChem and at least one further source.
On a certificate, an [M+H] ion is the molecule carrying one extra proton, so it reads at about the molecular
weight plus one; [M+2H] and [M+3H] carry two or three protons and read at about (MW + 2) ÷ 2
and (MW + 3) ÷ 3.
Lot
Ion
Calculated (average mass)
Detected
Difference
From the molecular weight printed on the certificate, 3326.8 g/mol
VIP10VAS0426
[M+2H]
1664.4
1664.7
+0.3
From amidated VIP, 3325.8 g/mol (Sigma-Aldrich, Cayman)
VIP10VAS0426
[M+2H]
1663.9
1664.7
+0.8
From the molecular weight printed on the certificate, 3326.8 g/mol
VIP10VAS0426
[M+3H]
1109.9
1109.8
−0.1
From amidated VIP, 3325.8 g/mol (Sigma-Aldrich, Cayman)
VIP10VAS0426
[M+3H]
1109.6
1109.8
+0.2
Calculated on an average-mass basis: the molecular weight printed on the certificate
(and, for comparison, amidated VIP's) plus 1.007 per proton, divided by the charge. The certificate doesn't state which basis the lab
reports or the instrument's mass accuracy, so the differences are shown, not graded.
Native VIP ends in an amide (…Ile-Leu-Asn-NH2):
C147H238N44O42S, 3325.8 g/mol (Sigma-Aldrich; Cayman), the figure on
our product page. The certificate prints 3326.8 g/mol, one unit more, which is the figure PubChem gives for a
structure ending in a free acid (CID 16132300, C147H237N43O43S). The
certificate prints no sequence or formula, so it doesn't say which form its 3326.8 refers to.
The detected ions don't settle it. A peptide of about 3,300 g/mol picks up several protons in the mass
spectrometer, so it reads at a mass-to-charge value well below its mass: (MW + 2) ÷ 2 for [M+2H]
and (MW + 3) ÷ 3 for [M+3H]. Dividing by the charge also divides the one-unit difference between
the two forms, to 0.5 and 0.3, so both readings sit within 1 of either basis (table above). The spectrum's tallest
peak, 832.3, and the peak at 666.5 are close to where the four- and five-proton ions would read (832.5 and 666.2 for
amidated VIP); the results table lists only the two- and three-proton ions.
What each test on the certificate means
UV purity
The lab separates the sample by liquid chromatography and records ultraviolet absorbance as it elutes.
UV purity is the target peak's share of the total peak area in the UV trace (at 208 nm where the
results table prints a wavelength). It counts only material that absorbs ultraviolet light: water, salts and the
counterion don't register, so it isn't the share of the powder that is peptide.
The certificate also states that salts and sugars present as fillers
aren't counted as impurities. A result written with “>”, such as “>99.3”,
is a lower bound, not an exact figure. A reproduced UV trace labelled XWC is extracted at the one
wavelength shown; one labelled TWC, a total-wavelength chromatogram, combines the detector's readings across its
wavelength range. More in
how peptide purity is measured and
how to read the HPLC chromatogram.
The results table gives UV purity at 208 nm, but the reproduced UV trace is
labelled TWC, a total-wavelength chromatogram, rather than a 208 nm trace, so the printed figure can't be read
directly off the trace. The main peak appears at 2.15 min.
Identity by LC-MS
The mass spectrometer reports ions by mass-to-charge ratio, and the certificate prints the molecular
weight next to the ion it detected. A detected ion close to the calculated value supports the identity of the
main component. It doesn't measure quantity, and molecules of the same mass (isomers) look alike to it.
Net weight measured
The lab's measured amount of material for the sample, printed beside the label claim where there is one.
The certificate doesn't say how it was measured, and it isn't net peptide content, which it doesn't report.
Endotoxin (LAL)
Bacterial endotoxin, the lipopolysaccharide of Gram-negative bacteria, measured with a Limulus amebocyte
lysate (LAL) assay and reported in endotoxin units per milligram of sample (EU/mg). The certificate prints the
value only, with no acceptance limit and no LAL method variant. More in
endotoxin on a peptide COA.
MFD and BBD
Manufacture and best-before dates, printed in the sample description next to the lot number.
The certificate reports no stability study, so a BBD is the date given for that lot, not a shelf life measured
under a stated storage condition.
Sample received and storage on receipt
When the lab received the sample, in what condition, and how the lab held it. That storage line is a
record of the lab's handling, not a storage recommendation.
Certificate ID and report date
The report's identifier and issue date. On most AxisPharm certificates in our library the ID begins with
the report date (13Jul2026-01 for a July 13, 2026 report, for example), which makes the two a useful
cross-check.
How to check this certificate
Match the lot. Find “Lot#” in the Sample Name line (VIP10VAS0426 on
that lot's certificate) and compare it with the lot number on the vial
label. A different lot number means a different certificate.
Check who issued it, and to whom. “From” names the laboratory; “To” names the
client the report went to.
Read the dates together. The report date, the date at the start of the Certificate ID, the
sample-received date and the MFD and BBD should tell one consistent story. Where they don't on the
certificates this guide goes through, the note on that certificate says so.
Compare the detected mass with the expected one. For an [M+H] ion, roughly the printed molecular
weight plus one. The identity table does this for each lot.
Read the purity with its method. A UV peak-area share, not the share of the powder that is
peptide.
Note the endotoxin unit. EU/mg, endotoxin units per milligram of sample.
Look for the traces. Two-page reports reproduce the UV chromatogram and the mass
spectrum.
Net peptide content: the share of the powder that is peptide.
Counterion identity and amount (trifluoroacetate or acetate, for example).
Water content and residual solvents.
The column, gradient and mobile phase behind the UV purity.
A stability study: the BBD is a date given for the lot, not a measured shelf life.
Identities for the other peaks in the reproduced mass spectrum: the results table names only the ions it reports.
Where this certificate comes from, and caveats
Who ordered the tests. PepsMartUSA didn't. AxisPharm, LLC issued the certificate, and our
supplier, Protixa, provided it to us. It is addressed to Protixa.
It prints Protixa as the brand name. More in
where the certificates come from.
No second laboratory. No second laboratory's result is published for this lot.
As provided. We publish each PDF as our supplier provides it and don't edit it.
One lot each. A certificate describes the sample the lab tested from one lot. The lot number is the
only link between a vial and a certificate. The laboratory's footer on each page
says the same: its analytical data apply only to the batch tested.
The vials are lyophilized (freeze-dried) powder. The label's storage line reads −20 °C long term,
2–8 °C short term, protect from light: the freezer for long-term holding, a refrigerator for a short hold,
dark and dry in both cases, with the seal intact. The certificate describes the material on its report date; storage affects how it changes afterwards. Full detail in peptide
storage.
VIP contains a methionine, a glutamine and three asparagines, residue types that Bachem's handling guidelines single out as limiting the shelf
life of a peptide (see peptide storage).
Why does the certificate's molecular weight differ from the product page's?
Our product page gives 3325.8 g/mol, the figure for native VIP, which ends in an amide
(C147H238N44O42S; Sigma-Aldrich, Cayman). The certificate prints 3326.8,
one unit more: the figure PubChem gives for a structure ending in a free acid. The certificate prints no sequence or
formula, and its detected ions fall within 1 of the values for either form, so it doesn't show which one was
tested.
Why does the VIP certificate list [M+2H] and [M+3H] rather than [M+H]?
A peptide this size usually carries more than one extra proton in the mass spectrometer, and the instrument
measures mass divided by charge. Amidated VIP is expected near 1663.9 with two protons and 1109.6 with three (1664.4
and 1109.9 from the printed 3326.8); the certificate reports 1664.7 and 1109.8. The single-proton ion would sit near
3327, beyond the 2,600 upper end of the reproduced spectrum.
Which vial does the VIP certificate describe?
Only the lot printed on it, VIP10VAS0426. A certificate describes the sample the
laboratory tested from one lot; the lot number on a vial's label is what ties that vial to a certificate. The
lot lookup opens the certificate for a lot number.
Did PepsMartUSA order this test?
No. AxisPharm, LLC issued the certificate and our supplier, Protixa, provided it.
It is addressed to Protixa and prints Protixa as the brand name. No second laboratory's result is published for
this lot.
For research use only. Not FDA approved, and not for
human or animal consumption. This certificate is a laboratory document about the material tested; nothing
on this page is an instruction for use of any kind. See the research use policy.
