DIN EN 16279:2012-09

In DIN EN 16279 an Ion-Selective Electrode method (ISE) after hydrochloric acid treatment for the determination of fluoride from animal feeding stuffs is specified. The determined content of fluoride corresponds to that of the fluorine content specified in Commission Regulation (EC) No. 574/2011. Fluorine is one of the most abundant elements in the environment. Animals are exposed to the ionic form of the element fluoride which may be present in feeding stuffs. The toxicity of fluoride has already been established by EFSA and its availability greatly depends on the solubility of fluoride compounds. In particular, fluoride compounds with low solubility are poorly absorbed while fluoride ions released from readily soluble compounds are almost completely absorbed from the gastrointestinal tract by passive diffusion in monogastric species. The extraction procedure of this method causes a mild acid treatment with hydrochloric acid solution of 1 mol/l which should reflect the typical gastric hydrochloric acid concentration of 0,1 mol/l to 0,3 mol/l. The method was successfully tested in an interlaboratory study in concentrations between 100 mg/kg up to 500 mg/kg. If this method is followed strictly, then theoretically all concentrations from 40 mg/kg up to 4 000 mg/kg can be analysed within the linear calibration function. Only for concentrations lower than 40 mg/kg is the use of an interpolation technique required instead of standard addition. The quantification limit for fluoride using the conventions of the method including the standard addition method is 40 mg/kg or lower than 2,5 mg/kg when using interpolation method. The European Standard has been prepared by CEN/TC 327 "Animal feeding stuffs - Methods of sampling and analysis", the secretariat of which is held by NEN (Netherlands). Collaboration of DIN for the field of responsibility of CEN/TC 327 is performed through the national mirror committee, Working Committee NA 057-03-03 AA "Futtermittel" ("Animal feeding stuffs") of NAL.