1 Scope
This standard specifies the determination of vitamin A in feeds and vitamin A acetate in vitamin premix by high performance liquid chromatography.
The Method I of this standard is applicable to the determination of vitamin A in formula feeds, concentrated feeds, compound premix and vitamin premix, with the quantitative limit as 1,000 IU/kg.
The Method II of this standard is applicable to the determination of vitamin A acetate in vitamin premix, with the quantitative limit as 344mg/kg (106 IU/kg).
2 Normative references
The following standards contain provisions which, through reference in this standard, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections) to, or revisions of, any of these publications do not apply. However parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent edition of the normative documents indicated below. For undated references, the latest edition of the normative document applies.
GB/T 603 Chemical reagent - Preparations of reagent solutions for use in test methods
GB/T 6682 Water for analytical laboratory use - Specification and test methods
GB/T 14699.1 Feeding stuffs - Sampling
GB/T 20195 Animal feeding stuffs - Preparation of test samples
3 Method I - Saponification extraction method
3.1 Principle
Vitamin A content is calculated by external standard method after the test sample is saponified with alkali solution to extract vitamin A with diethyl ether and distill off the solvent so that the residue can be dissolved in an appropriate solvent, which will be injected into a high performance liquid chromatograph for vitamin A separation and determination at 326nm wavelength.
3.2 Reagents and solutions
Unless otherwise specified, the reagents used in this standard are analytical reagents, water and chromatograph water meet the requirements of Grade 3 water and Grade 1 water in GB/T 6682, and solutions are prepared in according with Grade1 water requirements in GB/T 603.
Foreword i
1 Scope
2 Normative references
3 Method I - Saponification extraction method
4 Method II - Direct extraction
Annex A (Informative) Standard chromatograms of vitamin A and vitamin A acetate
