Physico-chemistry
The physico-chemistry section of the dossier relates firstly to the physical and chemical properties of a plant protection product. Secondly, the analytical methods are verified which are used to determine the active substance and relevant impurities in the formulation, and of residues in treated crops/fruits, food of animal origin, soil, air, water and in body fluids and tissues.
The legislation in this respect is based on Regulation (EU) no. 284/2013 (formerly Regulation (EC) no. 545/2011).
Physical and chemical properties
The physical and chemical properties of a plant protection product must comply with legal standards so that the product can be used safely, effectively and with ease.
The legal requirements for physico-chemistry concern general properties including
- content of the active substance
- oxidising and explosive properties
- flashpoint and flammability
- density
- surface tension
- viscosity
There are also specific properties which ensure the usability of a product, e.g.:
- particle size
- dust content
- foaming
- emulsifiability
- pourability
- dispersibility
These properties depend on the formulation type, ranging from solid (powder, granulate, tablet, etc.), liquid (solution, suspension, emulsion, etc.) to gaseous products. You can find various formulation types in the annex to the FAO specifications (see link below).
Another important aspect of a formulation is its stability, which is tested at various temperatures and different packaging materials if needed. In general, a product is expected to be stable for at least 2 years at room temperature. More information is available in the document "Extrapolation of packaging materials" for the possibility of extrapolation of studies for different packaging materials.
You can find a summary table of the required technical data here. The requirements are based on the previously mentioned Regulations and the FAO specifications. You can find the FAO manual here.
Analytical methods
Analytical methods are used to determine the content of the active substance and the relevant impurities in the formulation. The residues in treated crops/fruits, food from animal origin, soil, air, water and in body fluids are also analysed. It is essential that no unacceptable levels of (eco)toxic impurities are found in the product and that a sufficiently sensitive method is available for the detection of residues.
As such, these methods must be validated: validation vouches for the quality of the method used, and for the reliability of the results. The validation of the required methods is verified in the 'analytical methods' section of the dossier, and is laid down in the guidance documents of DG SANTE: