6490/1 (TSO International Standard INTE RNATIONAL ORGANIZATION FOR STANDARDIZATION ME XAYHAPOAHAR OPrAHW3AuMA nO CTAHAAPTW3AUWWORGANISATION INTE RNATIONALE DE NORMALISATION Ansi Intsrnat Doc Sect Animal feeding stuffs -- Determination of calcium content Part 1 : Titrimetric method Aliments des animaux -- Détermination de la teneur en calcium -- Partie 1 : Méthode titrimétrique First edition - 1985-11-01 ISO 6490/1-1985 (E) UDC 636.085/.087 : 543.24 : 546.41 Ref. No. 1SO 6490/1-1985 (E) Descriptors : animal feeding products, chemical analysis, determination of content, calcium, volumetric analysis. Price based on 2 pages Not for Resale Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through Iso technical committees. Each member body interested in a subject for which a technicaf committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with IsO, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISo Council. They are approved in accordance with iSO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 6490/1 was prepared by Technical Committee ISO/TC 34, Agricultural food products. Users should note that all International Standards undergo revision from time to time and that any reference made herein to any other International Standard impies its latest edition, unless otherwise stated. International Organization for Standardization, 1985 Printed in Switzerland Copyright International Organization for Standardization ISO 6490/1-1985 (E) INTERNATIONAL STANDARD Animal feeding stuffs -- Determination of calcium content Part 1 : Titrimetric method 4.7 Ammonium chloride, 50 g/l solution. 1 Scope and field of application This part of iSO 6490 specifies a titrimetric method for the 4.8 Bromocresol green, 0,4 g/l solution. determination of the calcium content of animal feeding stuffs 4.9 Potassium permanganate, standard volumetric sol- The method is applicable to all animal feeding stuffs having ution, c (1/5 KMnO4) = 0,1 mol/l. calcium contents greater than 1 g/kg. 2 References Apparatus is0 6490/2, Animal feeding stuffs - Determination of calcium Usual laboratory apparatus, and in particular content -- Part 2: Atomic absorption spectrometric method. 5.1 Electric muffle furnace, with air circulation, capable of. ISO 6497, Animal feeding stuffs -- Sampling. 1) being maintained at 550 ± 20 oC. Iso 6498, Animal feeding stuffs -- Preparation of test samples. 5.2 Incineration dish, made of platinum, silica or porcelain. 3 Principle 5.3 Sintered glass filter crucible, of porosity grade P 16 (pore size 10 to 16 μm). Ashing of a test portion, treatment of the ash with hydrochloric acid and precipitation of the calcium as calcium oxalate. Dissolution of the precipitate in sulfuric acid and titration with 5.4 Boiling water-bath. standard volumetric potassium permanganate solution of the oxalic acid formed. 5.5 Beakers, of capacity 250 ml. 5.6 Volumetric flask, of capacity 250 ml. 4 Reagents All reagents shall be of recognized analytical quality and the 5.7 Analytical balance. water used shall be distilled water or water of at least equivalent purity. 6 Sampling 4.1 Hydrochioric acid, approximately 30 % (m/ m) (020 = 1,15 g/ml). Take the laboratory sample as specified in ISO 6497. 4.2 Nitric acid, concentrated (g20 = 1,40 g/ml). 7 Procedure 4.3 Sulfuric acid, approximately 20 % (m/m) (220 = 1,13 g/ml). 7.1 Preparation of the test sample 4.4 : Ammonia solution, approximately 33 % (m/m) Prepare the test sampie in accordance with 1so 6498. (020 = 0,89 g/ml). 7.2Test portion 4.5 Ammonium oxalat