Quality and inspection
How to read a certificate of analysis.
A certificate of analysis states what a laboratory found in a sample. Whether it says anything useful about your container depends on which sample, which laboratory, which method and which date, and those four questions are the ones nobody asks.
Five checks.
Each takes a minute and together they catch most of what goes wrong with certificates in this trade. None of them requires technical knowledge.
- 01
Which sample
Does the certificate identify the lot that is shipping, by batch number or production date, and does that match your packing list? A certificate for a different batch is a certificate about somebody else's goods.
- 02
Which laboratory
In-house or independent, and accredited for what. A producer's own laboratory is not worthless and it has an interest. On anything where the number decides acceptance, independent is worth the cost.
- 03
Which method
Two laboratories using different methods produce different numbers on the same material, legitimately. If your specification names a method, the certificate has to use it or the comparison is meaningless.
- 04
Which date
Before or after the goods were packed. A result from material tested weeks before packing says nothing about moisture that was picked up since.
- 05
Which properties
Everything your specification asked for, or a subset. A certificate that reports four of your six properties has quietly not answered two questions.
What it does not prove.
That the rest of the container matches the sample. A certificate is analysis of a sample, and how representative that sample was depends on how it was taken. Sampling protocol is worth specifying on bulk agricultural goods.
That the goods are what they claim to be. Composition analysis on an essential oil establishes a profile. Species identification is a different test, and on products where substitution is the risk, that is the test you actually want.
That anything is safe. It reports numbers. Whether those numbers are acceptable is decided by your own market's limits and your own formulation, which is a question for your regulatory advisor rather than for the laboratory.
What to specify so the certificate is useful.
The properties, the limits, the method for each, and that the analysis is on the shipped lot. Then who takes the sample and how, because on bulk goods that is where representativeness is won or lost.
Where the value justifies it, split sampling: the producer's laboratory and an independent one on the same sample, with a retained portion sealed. It costs very little against a container and it converts a disagreement about results into a comparison.
Questions buyers ask.
Should I insist on an independent laboratory?
Where the number decides acceptance or price, yes. The cost is trivial against a container and the independence is the entire point. Where the analysis is routine confirmation of something visible, a producer's own result with a retained sample is often sufficient.
The certificate looks fine and the goods were not. Why?
Usually the sample. A certificate is honest about what was tested and says nothing about material it never saw. On bulk goods with variation, sampling protocol matters as much as the analysis, and it is the part almost nobody specifies.
Can a certificate be faked?
A PDF can be produced by anybody. That is one reason to name the laboratory in the specification and, where the value justifies it, to have the result confirmed with the laboratory directly. It is a five-minute check that is almost never done.
Read next.
Writing a specification suppliers can price
The document that decides what arrives. What belongs in it, what has to be measurable, and the words that cause disputes.
Inspecting before it sails
The five moments worth inspecting, what a report has to contain, and the mistake that makes an inspection worthless.
What a sample actually proves
The narrow question a sample answers, and why the sealed duplicate you never open is worth more than the one you evaluate.
Certificate of analysis
The laboratory report on a shipped lot. What belongs on it, why sampling matters more than the figures, and why retained samples settle disputes.
What to test, and where
Which properties need a laboratory rather than an inspector, and whether to test at origin or at destination.
Choosing a laboratory
Accreditation, scope, location and turnaround. Which decide whether a result is usable.
Sourcing from Indonesia?
Tell us the product, the quantity and the destination. We come back with what it involves before anyone talks about money.