Commission Regulation (EC) No 152/2009 of 27 January 2009 laying down the methods of sampling and analysis for the official control of feed (Text with EEA relevance) (c. 152)

ANNEX IV U.K. METHODS OF ANALYSIS TO CONTROL THE LEVEL OF AUTHORISED ADDITIVES IN FEED

D. DETERMINATION OF HALOFUGINONE U.K.

3. Reagents U.K.

3.1. Acetonitrile, equivalent to HPLC grade. U.K.

3.2. Amberlite XAD-2 resin. U.K.

3.3. Ammonium acetate. U.K.

3.4. Ethyl acetate. U.K.

3.5. Acetic acid, glacial. U.K.

3.6. Halofuginone standard substance (DL-trans-7-brome-6-chloro-3-[3-hydroxy-2-piperidyl)acetonyl] quinazoline-4-(3H)-one hydrobromide, E 764). U.K.

3.6.1. Halofuginone stock standard solution, 100 μg/ml U.K.

Weight to the nearest 0,1 mg, 50 mg of halofuginone (3.6) in a 500 ml graduated flask, dissolve in ammonium acetate buffer solution (3.18), make up to the mark with the buffer solution and mix. This solution is stable for three weeks at 5 ^oC if stored in the dark.

3.6.2. Calibration solutions U.K.

Into a series of 100 ml graduated flasks transfer 1,0, 2,0, 3,0, 4,0 and 6,0 ml of the stock standard solution (3.6.1). Make up to the mark with mobile phase (3.21) and mix. These solutions have concentrations of 1,0, 2,0, 3,0, 4,0 and 6,0 μg/ml of halofuginone respectively. These solutions must be freshly prepared before use.

3.7. Hydrochloric acid (ρ₂₀ approximately 1,16 g/ml). U.K.

3.8. Methanol. U.K.

3.9. Silver nitrate. U.K.

3.10. Sodium ascorbate. U.K.

3.11. Sodium carbonate. U.K.

3.12. Sodium chloride. U.K.

3.13. EDTA (ethylenediaminetetraacetic acid, disodium salt). U.K.

3.14. Water, equivalent to HPLC grade. U.K.

3.15. Sodium carbonate solution, c = 10 g/100 ml. U.K.

3.16. Sodium chloride-saturated sodium carbonate solution, c = 5 g/100 ml. U.K.

Dissolve 50 g of sodium carbonate (3.11) in water, dilute to 1 litre and add sodium chloride (3.12) until the solution is saturated.

3.17. Hydrochloric acid, approximately 0,1 mol/l. U.K.

Dilute 10 ml of HCI (3.7) with water to 1 litre.

3.18. Ammonium acetate buffer solution, approximately 0,25 mol/l. U.K.

Dissolve 19,3 g of ammonium acetate (3.3) and 30 ml of acetic acid (3.5) in water (3.14) and dilute to 1 1itre.

3.19. Amberlite XAD-2 resin preparation. U.K.

Wash an appropriate quantity of Amberlite (3.2) with water until all chloride ions have been removed, as indicated by a silver nitrate (3.20) test performed on the discarded aqueous phase. Then wash the resin with 50 ml of methanol (3.8), discard the methanol and store the resin under fresh methanol.

3.20. Silver nitrate solution, approximately 0,1 mol/l. U.K.

Dissolve 0,17 g of silver nitrate (3.9) in 10 ml of water.

3.21. HPLC Mobile phase. U.K.

Mix 500 ml of acetonitrile (3.1) with 300 ml of ammonium acetate buffer solution (3.18) and 1 200 ml of water (3.14). Adjust the pH to 4,3 using acetic acid (3.5). Filter through a 0,22 μm filter (4.8) and degas the solution (e.g. by ultrasonification for 10 minutes). This solution is stable for one month, if stored in the dark in a closed container.