What Buyers Should Check in a COA

A Certificate of Analysis (COA) is the bridge between a supplier’s promises and a verifiable batch. For dried herbal roots like Pseudostellaria heterophylla, knowing how to read one — and how to spot a weak one — is a core procurement skill.

First: does it describe your batch?

A COA is only meaningful if it is tied to a specific lot: batch/lot number, sample date and quantity. A beautifully printed “company COA” that is not batch-linked tells you nothing about the root you will receive.

Identity items

Look for botanical identification of the material — confirming the sample is Pseudostellaria heterophylla, not a substitute. For buyers with stricter requirements, macroscopic and microscopic identification or DNA-based identification can be requested through third-party laboratories.

Common test categories for dried roots

• Moisture — the single most practical quality figure for dried roots; it drives storage stability and price-per-active-kg
• Total ash and acid-insoluble ash — proxies for mineral/soil contamination and cleanliness
• Sulphur dioxide (SO2) — relevant where sulphur fumigation is still practised somewhere in the trade; many buyers require low or not-detected results
• Heavy metals — typically lead, cadmium, arsenic, mercury, per destination-market limits
• Pesticide residues — scope depends on the destination market and customer requirements
• Microbiology — more relevant for milled or extract forms than for whole dried root, but commonly requested

Red flags in a COA

• No batch number or a batch number that does not match the shipment
• A test scope that suspiciously avoids the category you asked about
• Round, identical numbers across different batches — a sign the document is a template, not a test
• No laboratory identification, or a lab you cannot verify

Before your first order, agree the exact test scope and destination-market limits with your supplier in writing — and keep every COA on file to compare across seasons. Our Quality & Traceability page shows how batch documentation fits into our supply chain, and our contact page is where current batch documents can be requested.