What to Ask When Something Looks Off
A Certificate of Analysis, or CoA, is the primary document that a chemical manufacturer issues to confirm that a specific batch of material meets its stated specifications. It travels with every shipment and sits at the centre of quality verification in pharmaceutical, food, and personal care supply chains.
Reading a CoA sounds simple until you try to explain why the assay result is reported as 99.2% when the specification says 98.5% minimum, or what it means that loss on drying came back at 0.4% versus a 0.5% maximum. This guide is for anyone who receives CoAs and wants to actually understand what they say.
A well-prepared CoA will always include certain information. If any of these are missing, that is itself a finding worth raising with your supplier.
Product name, grade, and CAS number
Batch or lot number (critical for traceability)
Manufacturing date and expiry or retest date
Test parameters, specifications, and actual results
Reference standard (e.g., USP, EP, In-house)
Authorised signature and issuing laboratory name
Assay
The assay tells you the purity of the active compound as a percentage. For pharmaceutical-grade glycine, you would typically expect an assay of 98.5% to 101.5% as per USP. A result at 97.8% is out of specification. A result at 102.1% may also be, depending on the monograph. Both should prompt a conversation, not an automatic acceptance.
Heavy Metals
Heavy metals testing is one of the most important parameters in pharmaceutical and food-grade materials. Results are typically reported in parts per million (ppm). For materials used in pharmaceuticals, the ICH Q3D guideline governs acceptable exposure limits by route of administration. A CoA that reports 'not detected' without specifying a detection limit is not giving you complete information.
Loss on Drying
This parameter tells you how much moisture or volatile substances are present in the material. In amino acids like glycine, excessive moisture can affect stability, microbial risk, and active content. A result approaching the maximum specification consistently across batches is worth monitoring over time, even if each individual batch passes.
pH
pH specifications matter particularly for materials used in pharmaceutical formulations or cosmetic products where pH balance is critical to both product stability and skin compatibility. A drift in pH between batches from the same supplier can indicate a process issue worth investigating.
Most CoA issues are not outright fraud. They are gaps in process, documentation habits, or quality management that accumulate over time. These are worth noting.
Results that are always exactly at the specification limit, batch after batch, which can suggest results are being adjusted rather than measured
Assay results reported without decimal places (99% versus 99.2%)
Missing or incomplete heavy metals panel for pharmaceutical-grade material
No reference to a pharmacopeial standard when claiming USP or EP grade
Issuing authority is listed as a sales office rather than a quality or analytical department
At Avid Organics, CoAs for AviGly™ (Glycine), AviGa™ (Glycolic Acid), and AviTau™ (Taurine) are issued by the in-house quality team, reference the applicable pharmacopeial standard for pharmaceutical-grade materials, and include the full analytical results panel rather than summary data.
If you have questions about specific test parameters or want to understand the reference standard behind a result, the technical team is available to walk through documentation. That kind of transparency is what a 19-year-old manufacturing operation with customers in 30 countries has to be able to provide.
Request a sample CoA or speak to the Avid Organics quality team at avidorganics.net/en/contact-us.
A Certificate of Analysis (CoA) is a quality document issued by the manufacturer that confirms a specific batch of material has been tested and meets the required specifications. It includes analytical test results, batch details, manufacturing information, and reference standards.
A CoA helps verify that the material complies with quality, purity, and safety requirements before it is used in manufacturing. It also provides traceability and supports regulatory compliance.
Start by verifying the product name, batch number, manufacturing and expiry/retest dates, test parameters, specifications, actual test results, reference standard (such as USP or EP), and the authorised quality department's signature.
Common warning signs include missing batch information, incomplete heavy metals testing, results consistently reported at specification limits, lack of reference to pharmacopeial standards, and CoAs issued without approval from the quality or analytical department.
Yes. Reputable manufacturers typically provide a sample Certificate of Analysis upon request so customers can review the analytical parameters, testing methods, and quality standards before placing an order.
