BS ISO 6495-1:2015 pdf download – Animal feeding stuffs — Determination of water-soluble chlorides content Part 1 : Titrimetric method.
4.6 Potassium chromate solution, mass concentration ρ(K 2 CrO 4 ) = 5 % in water (4.1). 4.7 Ammonium iron(III) sulfate, saturated solution. Prepare from NH 4 Fe(SO 4 ) 2 ⋅12H 2 O dissolved in water (4.1) until saturation. Approximately 125 g ammonium iron(III) sulfate per 100 ml water is required. 4.8 Activated carbon, free from chloride and not capable of adsorbing chloride. 4.9 Carrez I solution. Dissolve 10,6 g of potassium hexacyanoferrate(II) trihydrate [K 4 Fe(CN) 6 ⋅3H 2 O] in water (4.1). Dilute to 100 ml with water (4.1). 4.10 Carrez II solution. Dissolve 21,9 g of zinc acetate dihydrate [Zn(CH 3 COO) 2 ⋅2H 2 O] in water (4.1), and add 3 ml of glacial acetic acid. Dilute to 100 ml with water (4.1). 4.11 Sodium chloride, standard volumetric solution, c(NaCl) = 0,1 mol/l. The molarity of the standard volumetric solution shall be known to 0,000 1 mol/l. Put about 20 g of finely pulverized sodium chloride in a thin layer on watch glass. Dry at about 250 °C for 1 h to 2 h. Let it cool in a desiccator, accurately weigh 5,8 g, recorded to 0,000 1 g (m), and dissolve in water (4.1). Dilute to the mark in a 1 000 ml volumetric flask with water (4.1) and mix well.
6 Sampling Sampling is not part of the method specified in this part of ISO 6495. A recommended sampling method is given in ISO 6497. It is important that the laboratory received a sample which is truly representative and has not been damaged or changed during transport or storage. 7 Preparation of test sample Prepare the test sample in accordance with ISO 6498. If solid, grind a representative part, 100 g to 150 g of the laboratory sample (usually 500 g) so that it passes completely through a sieve with 1 mm apertures. Mix thoroughly. 8 Procedure 8.1 Preparation of test solution 8.1.1 General If the test sample is free from organic matter, proceed in accordance with 8.1.2. If the test sample contains organic matter, proceed in accordance with 8.1.3, unless the test sample concerns cooked feeding stuffs, flax cakes and flour, products rich in flax flour, and other products rich in mucilage or in colloidal substances (e.g. dextrinated starch). In this case proceed in accordance with 8.1.4.