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 III U.K. METHODS OF ANALYSIS TO CONTROL THE COMPOSITION OF FEED MATERIALS AND COMPOUND FEED

N. DETERMINATION OF ASH WHICH IS INSOLUBLE IN HYDROCHLORIC ACID U.K.

1. Purpose and Scope U.K.

This method makes it possible to determine the level in feed of mineral substances which are insoluble in hydrochloric acid. Two methods can be used, depending on the nature of the sample.

1.1. Method A: applicable to organic feed materials and to most compound feed. U.K.

1.2. Method B: applicable to mineral compounds and mixtures and to compound feed, whose content in substances insoluble in hydrochloric acid, as determined by Method A, is greater than 1 %. U.K.

2. Principle U.K.

2.1. Method A: the sample is ashed, the ash boiled in hydrochloric acid and the insoluble residue filtered and weighed. U.K.

2.2. Method B: the sample is treated with hydrochloric acid. The solution is filtered, the residue ashed and the ash thus obtained treated in accordance with Method A. U.K.

3. Reagents U.K.

3.1. Hydrochloric acid 3 mol/litre. U.K.

3.2. Trichloroacetic acid, solution 20 % solution (w/v). U.K.

3.3. Trichloroacetic acid, solution 1 % (w/v). U.K.

4. Apparatus U.K.

4.1. Hot plate. U.K.

4.2. Electric muffle-furnace with thermostat. U.K.

4.3. Crucibles for ashing made of silica, porcelain or platinum, either rectangular (approx. 60 × 40 × 25 mm) or circular (diameter: 60 to 75 mm, height: 20 to 40 mm). U.K.

5. Procedure U.K.

5.1. Method A U.K.

Ash the sample using the method described for the determination of crude ash. Ash obtained from that analysis may also be used.

Place the ash in a 250 to 400 ml beaker using 75 ml of hydrochloric acid (3.1). Bring slowly to the boil and boil gently for 15 minutes. Filter the warm solution through an ash-free filter paper and wash the residue with warm water until the acid reaction is no longer visible. Dry the filter containing the residue and ash in a tared crucible at a temperature of not less than 550 ^oC and not more than 700 ^oC. Cool in a desiccator and weigh.

5.2. Method B U.K.

Weigh 5 g of the sample to the nearest mg and place in a 250 to 400 ml beaker. Add 25 ml of water and 25 ml of hydrochloric acid (3.1) successively, mix and wait for effervescence to cease. Add a further 50 ml of hydrochloric acid (3.1). Wait for any release of gas to cease then place the beaker in a boiling water bath and keep it there for 30 minutes or longer, if necessary, in order to hydrolyse thoroughly any starch which may be present. Filter while warm through an ash-free filter and wash the filter in 50 ml of warm water (see observation 7). Place the filter containing the residue in a crucible for ashing, dry and ash at a temperature of not less than 550 ^oC and not more than 700 ^oC. Place the ash in a 250 to 400 ml beaker using 75 ml of hydrochloric acid (3.1); continue as described in the second subparagraph of 5.1.

6. Calculation of results U.K.

Calculate the weight of the residue by deducting the tare. Express the result as a percentage of the sample.

7. Observation U.K.

If filtration proves difficult recommence the analysis, replacing the 50 ml of hydrochloric acid (3.1) by 50 ml of 20 % trichloroacetic acid (3.2) and washing the filter in a warm solution of 1 % trichloroacetic acid (3.3).