ANNEX IISupplementary provisions
ANNEX II Method of determining the ash content of flour APPARATUS 1. Laboratory scales sensitive to 0,1 mg, box of corresponding weights. 2. Electric muffle kiln, with adequate draught and a temperature gauge and regulator. 3. Round, flat-bottomed incineration dishes (about 5 cm in diameter, maximum height 2 cm); preferably of gold and platinum alloy or of quartz or porcelain. 4. Desiccator (with an internal diameter of about 18 cm) fitted with a neck and a perforated plate, in porcelain or aluminium. Dehydration agent: calcium chloride, phosphorous pentoxide or silica gel coloured blue. METHOD 1. The weight of the test sample shall be between 5 and 6 g. When it is flour of which the ash content referred to dry matter is likely to be over 1 %, the weight of the test sample shall be between 2 and 3 g. The weight of the test sample may be rounded up to the nearest 10 mg; all other quantities are weighed to the nearest 0,1 mg. 2. Immediately before use the dishes must be heated in the muffle kiln at incineration temperature to constant weight; a period of 15 minutes is usually sufficient. The dishes are then cooled in the desiccator to laboratory temperature under the conditions indicated in point 7. 3. Place the test sample in the dish and spread it out in an even layer, without heaping. Immediately before incineration damp the test sample with 1 to 2 ml of ethyl alcohol. 4. Place the dishes in the mouth of the kiln, leaving the door open. When the substance has ceased to flame, push the dishes into the kiln. When the kiln door has been closed, an adequate draught must be maintained, but not so strong as to blow the substance out of the dishes. 5. Incineration must result in the total combustion of the flour, including any sooty particles among the ashes. It shall be considered completed when the residue is almost white after cooling. 6. The incineration temperature must reach 900 °C. 7. When incineration is completed, remove the dishes from the kiln and place them on a sheet of eternit for about one minute to cool, then put them in the desiccator (not more than four dishes at a time). The closed desiccator is placed near the analysis scales. Weigh the dishes when they are completely cold (about one hour). RESULTS 1. Margin of error: if the ash content does not exceed 1 %, the results of a double test must not differ by more than 0,02 units of ash content; if the ash content exceeds 1 %, the difference must not exceed 2 % of the ash content. If the difference exceeds these limits the test must be repeated. 2. The ash content must be expressed per 100 parts of dry matter and rounded up to 0,01.