Why is a sample collected at an exhibition often useless later?

Because it arrives without provenance. A useful sample is a quantity of material plus a statement of what it is, who provided it, from which batch, on what date and against which specification. Strip any one of those away and the remaining liquid cannot support a conclusion, because you can no longer order more of the same thing or explain in six months what you actually tested. The quantity is rarely the limiting factor. The missing paperwork almost always is.

Should samples be carried home personally?

Usually not. Chemical samples travel under the rules that apply to the material, regardless of how small the quantity is or what the occasion was, and hand luggage is the wrong channel for most of them. The workable approach is to agree at the stand that a documented sample will be shipped to your site by a proper channel with the correct classification and paperwork, and to treat anything handed over on the day as illustrative only. That also fixes the quantity problem, since a real trial needs more than anyone carries around a hall.

How much material should be requested?

Enough for the trial you plan, plus a retained portion that is never opened, plus a margin for the test you will think of afterwards. Decide the trial protocol before asking, because the protocol sets the quantity and a request with a stated purpose is taken more seriously than a vague one. Asking twice is normal and costs nothing; running a trial on too little material and having to repeat it later with a different batch costs the comparison itself.

What has to be on the label?

Material name and identifier, supplier and their reference, batch or lot number, date received, your own internal sample number, and the hazard information for the material. The internal number is what ties the container to the file, and it should be assigned on arrival rather than later. Write it so that it survives handling; labels rub, solvents dissolve ink, and a container whose marking has failed becomes waste even when the contents are perfectly good.

How long should samples and documents be kept?

Long enough to cover the life of any decision taken on them, which usually means longer than the sample itself stays representative. Keep the retained portion for as long as its own stability allows, note in the file when that period ends, and keep the documents for much longer than the material. When a formulation approved three years ago is questioned, the certificate, the specification and the trial record answer the question; the liquid, by then, may no longer resemble what was tested.

Making exhibition samples usable once you are home

Company news · Eapearl Chemical · 15 December 2025

Most samples brought back from an exhibition are never tested, and most of those that are tested cannot be turned into a purchase. The reason is almost never the material. It is that the bottle arrived without the information that makes a bottle into evidence.

What a sample actually is

A sample is not a quantity of liquid or powder. It is a quantity of material accompanied by a set of statements: what it is claimed to be, who provided it, which batch it came from, when it was taken, what specification it is offered against, and how it has been stored since. The material without the statements cannot support any conclusion, because you cannot reorder the same thing and cannot explain later what was tested.

This is why the collection problem is a documentation problem. The liquid in a stand sample is usually fine. What is missing is the batch number, the date and the name of the person who handed it over, and none of those can be reconstructed afterwards.

Agree the sample at the stand, receive it at the site

The practical rule is to separate the conversation from the shipment. At the stand, agree what will be sent: the material and identifier, the grade, the quantity, the batch, the documents to accompany it, and the delivery address. Confirm that agreement in writing the same week. Let the supplier ship it properly classified and properly documented to your site, where it can be received into the system like any other incoming material.

This solves three problems at once. It removes the transport question, since chemical samples travel under the rules of the material and not under the informality of the occasion, and small quantities in hand luggage are the wrong channel for most of them. It removes the quantity problem, because a meaningful trial needs more material than a visitor can carry. And it produces a paper trail from the beginning, which is the thing that was missing in the first place.

Anything actually handed over on the day is then a demonstration item: useful for showing a colleague what a pigment such as iron oxide red looks like out of the bag, not useful as the basis of an approval.

Labelling, numbered on arrival

Assign your own internal sample number as the container is received, before it goes anywhere. This number, not the supplier’s name, is what ties the material to the file.
Record material name and identifier, supplier and their reference, batch or lot number, date received and quantity.
Carry the hazard information for the material on the container, in the language of the people who will handle it.
Use marking that survives handling. Labels rub off, solvents dissolve ink, and an unreadable container becomes waste even when the contents are sound.
Photograph the container and its label on arrival and attach the image to the file, so that a later dispute about identity has something to refer to.
Split the material immediately into a trial portion and a retained portion, and never open the retained portion for convenience.

The file behind the bottle

The specification the material is offered against, in the supplier’s own words rather than a summary of them.
The batch certificate of analysis for the batch supplied, with methods named, not a generic example certificate.
The safety data sheet current at the date of supply, kept as the version received, since the version matters when a later question is about what was known at the time.
The correspondence that defines what was promised, including any statement about origin, route or intended use.
The trial protocol and results, including the control you compared against and its batch number. A result with no stated control is not a comparison.
A note of the conversation: who said what at the stand, their role, and how to reach them directly.

Keep these together under the internal sample number. Files organised by supplier name fragment when the supplier changes agent, changes name or is replaced by another entity in the same group.

Designing the trial before asking for material

Decide what the trial will measure and against what before requesting a quantity, because the protocol sets the quantity and a stated purpose gets a better sample. Always run the incumbent material alongside the candidate in the same session, on the same equipment, with the same operator. A candidate solvent such as butyl acetate from a new source is judged against your current source on the same day or not judged at all, because equipment, humidity and operator drift will otherwise be attributed to the material.

Test identity before performance. There is no point measuring gloss development from a new grade of titanium dioxide until you have confirmed that the material in the bag matches the certificate that came with it. Identity first, specification second, performance third, in that order, because a failure at each stage means something different and the later stages waste effort if the earlier ones were skipped.

Retention, and the day the sample stops being evidence

A retained portion is only useful while it still resembles what was tested. Note in the file when its useful life ends, based on the material and the storage you can actually provide, and store it accordingly: closed, cool, dark, and away from anything that would contaminate it. When that date passes, the retained portion stops being a reference and the file becomes the only record that survives.

The documents should therefore outlive the material by a long margin. When a formulation approved years earlier is questioned, the question is answered by the specification, the certificate and the trial record. That is also why the safety data sheet should be kept as received rather than replaced by the current version: the file is a record of what was known and agreed at a date, not a library of current documents.

The failure modes worth naming

A bottle with no batch number, which cannot be reordered and cannot be defended.
A sample tested against no control, producing a number that means nothing.
A sample quietly consumed down to nothing, leaving no retained portion when a dispute arises.
A certificate that is a generic example rather than the certificate for the batch received.
A file kept in one person’s inbox, which leaves the company when they do.
A trial run so long after collection that the material is no longer representative of what was supplied.

All six are cheap to prevent at the moment of collection and impossible to repair afterwards. If a sample already in your store lacks its batch documentation, the fastest remedy is usually to ask the supplier to reissue the paperwork against the batch number on the label, or to send a fresh documented sample; both requests can be made through our contact page.