A specification for an agrochemical technical sets out exactly what the product is, how pure it must be, which impurities are limited and how each is measured. Base it on your registration, the supplier's five-batch analysis and any FAO specification for the active.
The specification is the document you test against and claim against. If a property is not in it, you cannot reject a lot for failing it.
What to include
- Identity: state the common name, chemical name, CAS number and molecular formula, and the identity test, such as an infrared spectrum or HPLC retention time.
- Purity: set the minimum active content in g/kg, with the method named, such as a validated HPLC or GC method or a CIPAC method.
- Relevant impurities: list each toxicologically relevant impurity with its maximum level and method, taken from your registration.
- Other impurities: set a limit for any single unknown impurity and for total impurities, where your regulator or the FAO specification uses one.
- Water content: set the maximum and the method, usually Karl Fischer.
- Acidity or alkalinity, or pH: set a range where it affects stability or formulation.
- Physical form and appearance: describe the colour, form and, for solids, particle size where it matters to your process.
- Isomer ratio: state the range for actives sold as a defined isomer mix.
Where the numbers come from
Your registration fixes the minimum purity and the relevant impurity limits. Your specification must be at least that strict. Where an FAO specification exists for the active, it gives a useful reference for limits and methods, but your regulator's decision comes first.
The supplier's five-batch analysis shows what the process actually achieves. Set limits the process can meet consistently, but not so loose that drift goes unnoticed. If a supplier cannot meet your registered limits on five batches, it is the wrong source.
Sampling, release and commercial terms
- Sampling: state how many containers are sampled per lot, who draws the samples and how retention samples are kept.
- Release: require a COA for each lot that reports every specification item, and state whether an independent lab must test before shipment.
- Packing: specify the drum or bag type, liner, net weight, labelling and UN approval where the technical is dangerous goods.
- Shelf life: set the retest date and the minimum remaining life at shipment.
- Change control: require written notice before any change of route, key raw material or site.
- Disputes: name an umpire lab and the method used if results differ.
Keep it a controlled document
Give the specification a number and a version, and have both sides sign it. Refer to that version in every purchase order and contract. Our guide on what a chemical purchase contract should include shows how the two fit together. Update the specification when your registration changes, and tell the supplier in writing.
Next step
We help you turn registration limits into a working specification, then have each lot tested against it. Book a free sourcing review to start.