A certificate of analysis is only worth what the sampling behind it is worth. The sample has to be representative of a well mixed batch that nothing is added to afterwards, the laboratory has to be able to run every method in the scope in house, and the methods themselves have to be the ones the buyer screens on. Get those three right and one analysis can cover a whole shore tank batch, which is also how the cost per tonne comes down.
- 1Origin of the material
- 2Chain of custody
- 3Mass balance bookkeeping
- 4Scheme certificate
- 5Claim on the invoice
A claim is only as good as the weakest box to its left.
The sample decides everything after it
A sample drawn from a well mixed shore tank, where the batch is closed and no further material is added after the sample is taken, can be treated as representative of that batch. That is the condition, and it is worth stating in writing rather than assuming, because it is what allows one certificate of analysis to cover everything loaded out of that tank.
The practical consequence is money. If four isotanks are filled from one shore tank batch, they can move on the same CoA. Producers running six small tanks of thirty cubic metres each cannot spread the cost of an external batch analysis over enough volume, and it shows up in their offer. This is a real constraint on small producers, and it is often the reason a first parcel prices badly.
The laboratory has to be able to run the whole scope
The certificate needs to come from a laboratory that can perform every test in the agreed scope, with the applicable method modifications, in house. A laboratory that subcontracts half the parameters produces a report that takes longer, costs more and is harder to defend when a result is questioned.
Ask for written confirmation that the full scope runs in house before the first sample is sent. We do this routinely for parcels we are placing, and it has saved more than one qualification round.
Methods matter as much as numbers
A parameter without its method is not a specification. The same property reported by two different methods can produce numbers that are not comparable and a discussion that goes nowhere. Three that come up constantly in pyrolysis oil:
- Halogens. It helps a great deal if chlorine is run as total halogens by ASTM D7359, with chlorine and bromine reported separately. A single combined figure hides which of the two you are dealing with, and they are not the same problem.
- Metals. Usually ASTM D5185, frequently with a modification for this matrix. If a specification sheet gives a modification note, check that the note and the parameter table name the same method; we have found them disagreeing.
- Distillation cuts. Some parameters, total oxygenates and benzene among them, call for an ASTM D1160 distillation followed by analysis on a specific cut. That is two operations, and a laboratory quoting only the second has not quoted the job.
Qualification, then routine
The scope at qualification and the scope per batch are usually not the same, and this is worth agreeing before anyone starts spending money. The questions to settle with the buyer are simple and rarely asked early enough:
- Do they expect a certificate of analysis on every batch covering the full parameter list, or a reduced routine set per batch with the full list at qualification and then at intervals?
- Is one analysis per shore tank acceptable, or do they want it per production batch?
- What batch size is workable as a starting point while a producer builds up?
- Who pays for what, and at whose cost the assessment tests are run.
Timing is part of the specification
Analysis takes days. Production, sampling, testing and loading all have to be synchronised around one batch, and a producer who has not planned for that discovers it at the worst moment. When we set up a first movement we work the timing backwards from the loading window, not forwards from production.
Where we come in
We can put you in touch with laboratories and inspection companies for the analysis itself, including in the origin country, and we regularly obtain quotations on a producer's behalf so that the method list goes out complete rather than in pieces. Where a specification is covered by an NDA we pass on the test methods and modification notes only, without categories or specification values, so a laboratory can quote without seeing anything it should not.
We are a broker. We do not run tests, we do not issue certificates, and we do not stand behind a laboratory's result. What we do is make sure the right questions are asked before money is spent, and read the report against what the buyer will actually do with it.
Frequently asked questions
What makes a sample representative?
It has to come from a well mixed shore tank that is then batched, with no further material added to the batch after the sample is drawn. Under that condition the analysis can be treated as covering the whole batch, including every isotank loaded out of it. State the condition in writing; do not assume it.
Can one certificate of analysis cover several isotanks?
Yes, if they are all loaded from the same closed shore tank batch that the sample represents. That is also how the cost of testing comes down per tonne, which matters a great deal to smaller producers.
Which laboratory should we use?
One that can run every method in the agreed scope in house, including the modifications. Ask for written confirmation of that before the first sample is sent. We can introduce you to laboratories and inspection companies, including in the origin country, and we often obtain the quotation on the producer's behalf.
How should chlorine be reported?
It helps considerably if it is run as total halogens by ASTM D7359, with chlorine and bromine reported separately. A single combined halogen figure leaves the buyer unable to tell which of the two they are dealing with, and they are different problems with different consequences downstream.
Do we need a full analysis on every batch?
That is a question for the buyer and it should be settled at qualification. Some ask for the full parameter list on every batch; others accept a reduced routine set per batch with the full list at qualification and then at intervals. The answer changes the cost per tonne significantly.
How long does the analysis take, and does that matter?
Days rather than hours, and yes. Production, sampling, testing and loading have to be synchronised around a single batch. Work the timing backwards from the loading window; producers who plan forwards from production tend to discover the problem when a vessel is waiting.
Our specification is under an NDA. Can a laboratory still quote?
Yes. A laboratory needs the test methods and any modification notes to price the work. It does not need the categories or the specification values. We pass on the methods only, so a quotation can be obtained without disclosing anything covered by the agreement.
Who pays for the analysis?
It varies, and it should be agreed before samples move. Assessment tests run to establish whether a laboratory can do the work are commonly at the seller's cost. For the trade itself, inspection at the load port is frequently split, but that is a term to negotiate rather than a rule.
The specification sheet contradicts itself on a method. What now?
Ask, before anyone spends money. We have found parameter tables and modification notes naming different methods for the same property. It is almost always a typographical error rather than a disagreement, but a laboratory quoting against the wrong one produces a report the buyer will not accept.
Market news
Recent headlines from across the feedstock and renewable fuel sector. Nothing specific to this market has come through the wires lately, so this is the wider view. The links go to the publisher; we do not host or edit their reporting, and a headline here is not our endorsement of it. Scroll for more.
- Call for papers on AI for circular economy: Intelligent algorithms for sustainable resource recovery
- NEDO, Kyoto University build world’s first hydrogen beamline at SPring-8-II
- Air Products and Nobian sign long-term agreement for RFNBO-compliant hydrogen
- Romania’s Senate approves green hydrogen law
- Namibia pioneers Africa’s first green hydrogen facility
- Hamburg starts building hydrogen connector for HH-WIN network
- Commercial use of green hydrogen gets under way in Czechia
- Kawasaki Heavy starts Kawasaki hydrogen plant with 18-ton daily capacity
- The Navy, Amyris, Emvolon, Haffner Energy and the Incredible Shrinking Refinery
- ICM supplying processing tech for Atvos’ Brazilian corn ethanol production plant
- Outage at South Africa’s Natref refinery
- Australian Government releases national maritime emissions reduction plan
- Circularity Communicated Conference 2026
- Circular fashion: Design, science and value in a sustainable clothing industry
- nova-Institute hosts the chemical industry defossilisation summit
- Quick Scan Circular Business Models
- Rubbermaid Brilliance line expands with Eastman’s Tritan Renew
- New ABC data reveals how America’s biogas is used today
18 headlines, updated automatically. Last refreshed .
Sources and further reading
Primary sources for the rules and figures on this page, so you can check them yourself. Legislation is amended: always read the consolidated text on the date that matters to you.
Who to ask about Sampling and laboratories
Just ask. Preparing a qualification sample, or holding a CoA a buyer has queried? Send the report and the method list and we will tell you what a buyer will do with it. You get Bart van den Brug on the other end, same working day, in English or Dutch, and across the team also in French, Portuguese, Polish, Czech and Russian.
On how we work: on the feedstocks and fuels on this site we are a broker. We never take title, we do not trade our own book, and we are paid a commission on business that concludes. Additives are the one exception: those we also buy and sell for our own account, and we say in which capacity we are acting before you commit to anything. Either way you will hear it from us when the answer is no, or when your parcel is not ready for the conversation you want to have. A market read or a second opinion on a specification costs nothing and commits you to nothing.
Happy to look at whatever you have, even if it is half an analysis and a question.
+31 6 115 83 448
bart@sustainablecommodities.eu
Sustainable Commodities 3 B.V., Lemmer, the Netherlands
Ask about Sampling and laboratories
A direct line to the desk. We answer the same working day in almost all cases, and we will tell you plainly when a cargo is not something we can place.
Prefer email? bart@sustainablecommodities.eu · +31 6 115 83 448
Last reviewed 02 September 2026. Regulatory references are given for orientation and are not legal advice: verify against the current Official Journal text before contracting.