DOCUMENTED BY BATCHA Certificate of Analysis (COA) is the document that records what a research peptide vial actually contains and how that was measured. It is the single most useful reference a laboratory has when logging a compound into an inventory, because it ties a physical vial to a specific batch and a specific set of analytical results. Every batch sold through livvmore is identity- and purity-tested at the USC Alfred E. Mann Multi-Omics Mass Spectrometry Core, a university laboratory, by liquid chromatography-mass spectrometry (LC-MS) and high-resolution mass spectrometry (HRMS), and the resulting COA is published per batch. This guide walks through each field so the numbers can be read and cross-checked with confidence.
What a Certificate of Analysis is
A COA is a structured test report issued by the laboratory that ran the analysis. It states the compound tested, the batch it came from, the analytical methods used, the results those methods produced, and the identity of the analyst and lab. A COA describes chemistry and measurement only. It is not a usage document, and it makes no claim about anything beyond what the instruments recorded.
Compound identity, batch and lot number
The top of a COA names the compound and pins it to a batch or lot number. The compound name should correspond to a known chemical identity you can verify independently against a public database such as PubChem. For example, Retatrutide (house code GLP3-RT) carries CAS number 2381089-83-2, molecular formula C221H342N46O68, and a molecular weight near 4731.3 g/mol. Tirzepatide (GLP2-TZ) is CAS 2023788-19-2, C225H348N48O68, about 4813.5 g/mol, and Semaglutide (GLP1-SM) is CAS 910463-68-2, C187H291N45O59, roughly 4113.6 g/mol. A shorter peptide such as BPC-157 is CAS 137525-51-0, C62H98N16O22, near 1419.5 g/mol, a 15-residue sequence. The batch or lot number is what makes a COA traceable: it should match the label on the vial exactly, so the certificate in hand describes the material in hand and not a different production run.
Purity percentage and how it is calculated
The purity figure is usually a chromatographic purity, reported as a percentage. In a high-performance liquid chromatography (HPLC) run, the detector produces a chromatogram of peaks over time, and each peak’s area is integrated. Chromatographic purity is the area of the main peak expressed as a percentage of the total integrated area of all peaks. A result such as 99.2 percent means the target peak accounts for 99.2 percent of the detected signal, with the remainder being related peaks and impurities. Purity is a relative measurement tied to the method and detection wavelength used, which is why a COA states the method alongside the number rather than the percentage on its own.
Analytical method: HPLC versus LC-MS and HRMS
A COA typically reports two different kinds of test because they answer two different questions. HPLC answers “how pure is it” by separating components and quantifying peak areas. Mass spectrometry answers “is it the right molecule” by measuring mass. In LC-MS, the chromatographic separation is coupled to a mass detector, so each peak can be assigned a mass. High-resolution mass spectrometry (HRMS) measures that mass precisely enough to confirm the molecular formula. Reading both together is what separates a genuine identity confirmation from a purity number alone, and it is why livvmore’s batches are run on mass-spectrometry instruments at the USC core rather than by a single chromatographic pass.
Retention time, mass accuracy and the observed mass
Two numbers confirm that the peak measured is the intended compound. Retention time is the point, in minutes, at which the compound elutes from the HPLC column under the stated conditions; a consistent retention time across batches is a fingerprint for the same molecule on the same method. Mass accuracy, usually given in parts per million (ppm), is the deviation between the mass the instrument observed and the theoretical mass calculated from the molecular formula. A small ppm figure indicates the observed mass closely matches the expected mass. Some COAs also list the observed monoisotopic or average mass directly, which can be checked against the molecular weight referenced above.
Analyst, laboratory and date
A complete COA identifies who performed the analysis and when. Look for the laboratory name, an analyst or signatory, and an analysis date. The laboratory attribution is what makes third-party testing meaningful, because it names the party accountable for the result. On a livvmore COA this is the USC Alfred E. Mann Multi-Omics Mass Spectrometry Core, and the date lets you match the certificate to the correct production batch over time. You can review how each batch is documented on the quality and testing page.
Cross-checking a COA against the vial
Reading a COA well comes down to matching four things: the compound name against a verifiable chemical identity, the batch number against the vial label, the purity method against the purity figure, and the observed mass against the theoretical molecular weight. When all four line up, and the testing laboratory is named, the certificate is doing its job as a reference document for laboratory records.
For laboratory research use only. Not for human or veterinary use.
Frequently asked questions
What does the purity percentage on a peptide COA mean?
On a research peptide Certificate of Analysis, the purity percentage is normally a chromatographic purity from an HPLC run. The instrument integrates the area of every detected peak, and the purity figure is the main peak's area expressed as a percentage of the total area. A value of 99.2 percent means the target peak represents 99.2 percent of the detected signal. It is a relative measurement tied to the stated method and detection wavelength, so a COA reports the method alongside the number.
What is the difference between HPLC and LC-MS on a COA?
HPLC (high-performance liquid chromatography) and LC-MS (liquid chromatography-mass spectrometry) answer different questions on a COA. HPLC measures purity by separating components and quantifying peak areas. LC-MS and high-resolution mass spectrometry (HRMS) confirm identity by measuring the molecular mass of each peak precisely enough to match the expected molecular formula. A thorough COA reports both, so purity and identity are each documented rather than inferred.
What CAS number and molecular weight should a Retatrutide COA match?
Retatrutide (house code GLP3-RT) has CAS number 2381089-83-2, molecular formula C221H342N46O68, and a molecular weight near 4731.3 g/mol as listed on PubChem. A COA's stated identity and observed mass should be consistent with these values. It is a 39-amino-acid synthetic peptide, and the batch number on the certificate should match the vial label exactly.
What is mass accuracy in ppm on a peptide certificate?
Mass accuracy, expressed in parts per million (ppm), is the deviation between the mass a mass spectrometer observed and the theoretical mass calculated from the compound's molecular formula. A small ppm figure means the measured mass closely matches the expected mass, supporting the identity assignment. It appears on COAs that include high-resolution mass spectrometry (HRMS) data alongside the observed monoisotopic or average mass.
Who tests livvmore research peptides and how?
Every livvmore batch is identity- and purity-tested at the USC Alfred E. Mann Multi-Omics Mass Spectrometry Core, a university laboratory, using LC-MS and high-resolution mass spectrometry (HRMS). Testing is done per batch and the resulting Certificate of Analysis is published, so the compound name, batch number, purity method and observed mass on the certificate can be cross-checked against the vial.