Reading a COA without guessing — post one you're unsure about and we'll walk through it

A certificate of analysis is only useful if you can read it. This is a how-to-read thread, not a vendor-rating thread. Post a COA you're unsure about — identity, purity %, the mass-spec / HPLC trace, what the method actually tells you — and the thread will walk through what each part means. Keep sourcing and where-to-buy out of it; that lives on the deals board.