Methods
Ask a question first, then pick a method
The panel is the set of questions you need answered. A purity percentage does not answer an endotoxin question, and an endotoxin result does not answer a sterility question.
| Question | Method that can answer it | What it does not answer |
|---|---|---|
| Is the major peak the named compound? | Retention time and spectrum against a reference standard, or a mass from LC-MS / ESI-MS | Retention time alone is weaker than a mass. Neither line is a purity percentage. |
| What share of the signal is the main peak? | HPLC or UHPLC area percent | Not the milligrams in the container. |
| How many milligrams are in the container? | Content or assay against a quantitative standard | Not the area-percent purity. |
| Is bacterial endotoxin reported? | LAL or another method the laboratory names, sometimes cited as USP <85> | Not sterility, and not identity. |
| Are viable microbes reported? | A count such as TAMC/TYMC or bioburden, a PCR screen, or a sterility method the laboratory names | Those phrases are not the same claim. Read the method line. |
| Are specified elements reported? | ICP-MS or another elemental method the laboratory names | Not identity or purity. |
Heavy metals and amino acid analysis show up on some laboratory menus. They are additional questions, not substitutes for identity and purity. Amino acid analysis speaks to composition after hydrolysis. It is not a chromatogram of the intact peptide.