COA Reading Room · Teaching resource 1.0

Fictional peptide COA review exercise

Practice reading a peptide certificate of analysis: trace three vial labels to a fictional report, compare each result with its own criterion, and document what remains open.

Fictional teaching example. Organizations, identifiers, dates, values and criteria were created for instruction. No sample was tested, and this document does not certify a material.

Before you start

Estimated time 20–30 minutes.

Prerequisites Basic percentage arithmetic and familiarity with a lot or batch number. Use a spreadsheet for the CSV or write your notes on paper.

Learning objectives

Teaching report: TCOA-024

Review the document record, the results and then the possible vial labels. Keep document evidence and your interpretation in separate columns. ICH Q7 provides background on certificates for active pharmaceutical ingredients.

Document record
FieldFictional entry
Issuer and authorizationTraining Lab 04; authorized in simulation by teaching reviewer TR-04
Report ID / revision / pageTCOA-024 / Rev 01 / page 1 of 1
MaterialUnmodified linear hexapeptide GAGKLV with free N and C termini. Catalog EDU-HX06. Nominal 5.0 mg per vial, peptide basis.
Supplier lot / laboratory accessionEDU-L-0042 / EDULAB-0251
Sample descriptionOne sealed teaching vial submitted by Classroom Supplier 02. The issuer’s intake record links it to lot EDU-L-0042; it gives no individual vial identifier.
DatesReceived 2026-08-10; tested 2026-08-12; report issued 2026-08-13
Attachments referencedTCOA-024-M (deconvoluted LC–MS spectrum); TCOA-024-H (HPLC trace and integration); TCOA-024-A (assay calculation). Attachments are intentionally absent from the exercise.
Reported test results
AttributeFictional methodStated criterionReported result
Mass match supporting identityLC–MS, M-07 Rev 02; deconvoluted neutral monoisotopic massWithin ±0.010 Da of 543.338 Da543.339 Da
Main peak relative areaRP-HPLC/UV, H-04 Rev 03, 214 nm≥97.0 area% of integrated peaks98.4 area% (984 of 1,000 integrated signal-area units)
Peptide amount per tested vialCalibrated HPLC/UV assay, A-02 Rev 01; assigned-content reference4.50–5.50 mg peptide equivalent per vial4.70 mg peptide equivalent per tested vial

Practice: compare the received labels

Alternative labels for the vial on your bench
CaseCatalogLotVial ID
AEDU-HX06EDU-L-0042BOX2-05
BEDU-HX06Not recordedBOX2-06
CEDU-HX06EDU-L-0043BOX2-07
  1. For each label, record whether the lot matches, is missing or conflicts. What does the document establish about the specific vial?
  2. Compare each test result with its own criterion. State its unit and denominator or measurement basis.
  3. A colleague multiplies 5.0 mg by 98.4% and records 4.92 mg per vial. Explain why this is an unsupported substitution and locate the reported amount.
  4. What would you request to check the area calculation and connect the report to Case A’s vial? Draft a one-sentence decision note with a next action.

Worked answer key

  1. A: Lot matches as written. The lab tested a submitted vial linked to the lot, and did not record its individual vial identifier. The report cannot show that the lab tested BOX2-05. B: Lot missing; obtain the intake or packing record before attributing the report to the vial. C: Lot conflicts; retain the discrepancy and request the report for EDU-L-0043 or a documented correction.
  2. Mass: 543.339 − 543.338 = +0.001 Da, within the stated tolerance; a mass match alone cannot establish residue order or rule out isobaric alternatives. Area: 100 × 984 / 1,000 = 98.4 area%, which meets the 97.0 area% minimum. Amount: 4.70 mg peptide equivalent per tested vial falls in 4.50–5.50 mg.
  3. The 5.0 mg value is a nominal label amount. The 98.4% fraction is a share of integrated UV signal under one method. It is not a mass fraction; the calculation cannot replace the separate calibrated assay of 4.70 mg.
  4. Request TCOA-024-H, the integration rules, and the packing or inventory record linking BOX2-05 to the lot. Example: “Lot EDU-L-0042 matches the vial label; results meet the printed criteria for the submitted sample; confirm the container trail and review the referenced integration file before relying on the result.”

Instructor notes

  • Give learners the report and labels first. Ask them to explain what Case A establishes about the lot and what remains open about vial BOX2-05.
  • Compare the evidence learners cite for each result. Look for a correct denominator for area percentage and a separate calibrated assay for the vial amount.