This document specifies a method for the determination of benzoic acid and sorbic acid in animal feeding stuffs by high-performance liquid chromatography method with ultraviolet detection (HPLC-UV).
The method is intended to be used for the determination of benzoic acid and sorbic acid as active substances in feed additives, premixtures, feed materials and compound feed and for benzoic acid in water. This method determines the total extractable concentration of these organic acids and their salts.
It is advisable that the working range of the method is determined for each organic acid by the user of this standard. The lower limit of the working range depends on the matrix and the interferences encountered. It is advisable that a working range between 5 mg/l and 100 mg/l is accessible.
The method was successfully tested in an inter-laboratory study in concentrations between 0,02 % up to 9,0 %.
On the basis of the referred working range, sample weight and extraction volume, limits of quantification (LOQ), as calculated (Table 1) on the basis of a wavelength of 230 nm, can be achievable.