ANALYTICAL METHODS · PRACTICAL GUIDE
COA, SDS and Raw Spectra: Which Document Answers Your Question?
Choose the document that answers your question: test results, safety, or analytical signals.
You receive a safety data sheet for a peptide. Can it tell you the batch’s purity? Usually that is not its purpose. COAs, SDSs and spectra answer different questions. Knowing which one to read saves you from searching the wrong document.
Put the three documents side by side
A COA, or certificate of analysis, records stated tests and results for the identified material or batch. An SDS, or safety data sheet, organizes hazard and handling information. Analytical plots show the signals behind particular measurements.
A simple way to choose: “What was measured?” points toward analytical results; “How do I handle this material?” points toward the SDS; “What does this peak mean?” needs the plot and method.
If you have a COA, read the actual rows
Check the material name, batch identifier, test, method and reported result. A test not listed is not automatically a passed test. A general specification or example certificate may not refer to your actual vial.
Keep any stated criteria and confirmation details with the results. They help explain what the document actually declares.
Use the SDS for hazards and handling
An SDS is organized into sections covering matters such as identification, hazards, first aid, handling, storage and exposure controls. The section headings help you find a particular safety question.
Make sure it matches the material and supplier. It does not normally establish a batch’s HPLC percentage or target-peptide amount.
A spectrum needs its labels and method
A chromatogram needs axes, method details and an explanation of the target peak. A mass spectrum needs an explanation of the ions, charges and reference masses. A cropped image of only the tallest peak can remove important context.
Match the sample name and batch information to the record before interpreting the numbers. Ask whether fuller data or processing details are available when needed.
What if the document is missing?
Ask which information can actually be supplied. Do not fill a missing result with a number from a different document. NHD currently does not provide COAs; this is a guide to reading them, not an offer of an NHD certificate. Other records need individual confirmation.
See the answer
No. This document provides no basis for that percentage. Ask which analytical results are available.
Requesting information for GHK-Cu or LL-37
Name the exact GHK-Cu or LL-37 variant and explain the question you need the information to answer. Confirm the records available now rather than assuming a particular certificate or analysis is included.
Discuss material and document requirements with NHD · Continue with the analytical guide