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1、BRITISH STANDARD BS 5766-5: 1981 ISO 6495:1980 Incorporating Amendment No. 1 Methods for Analysis of animal feeding stuffs Part 5: Determination of water-soluble chlorides content ISO title: Animal feeding stuffs Determination of water-soluble chlorides content UDC 636.085:543.831:546.131 Licensed C
2、opy: sheffieldun sheffieldun, na, Mon Dec 04 14:28:21 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5766-5:1981 This British Standard, having been prepared under the direction of the Food and Agriculture Standards Committee, was published under the authority of the Executive Board and comes into eff
3、ect on 31 August 1981 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference FAC/14 Draft for comment 79/50914 DC ISBN 0 580 12196 8 Cooperating organizations The Food and Agriculture Standards Committee, under whose direction this British Standard was prep
4、ared, consists of representatives from the following: Agricultural Cooperation and Marketing Services Agricultural Research Council, Meat Research Institute British Food Manufacturing Industries Research Association British Industrial Biological Research Association Ltd. Campden Food Preservation Re
5、search Association Consumer Standards Advisory Committee of BSI Department of Agriculture and Fisheries for Scotland Department of Agriculture (Government of Northern Ireland) Department of Industry (Laboratory of the Government Chemist)* Flour Milling and Baking Research Association Food and Drink
6、Industries Council Food Manufacturers Federation Incorporated Institute of Brewing Local Authorities Co-ordinating Body of Trading Standards Ministry of Agriculture, Fisheries and Food* National Farmers Union* National Farmers Union of Scotland Tobacco Advisory Council The organizations marked with
7、an asterisk in the above list, together with the following, were directly represented on the Technical Committee entrusted with the preparation of this British Standard: Association of Fish Meal Manufacturers Association of Public Analysts Federation of Gelatine and Glue Manufacturers Limited Grain
8、and Feed Trade Association Limited National Cattle Breeders Association Overseas Development Administration (Tropical Products Institute) Royal Association of British Dairy Farmers The Pet Food Manufacturers Association United Kingdom Agricultural Supply Trade Association Ltd. Amendments issued sinc
9、e publication Amd. No.Date of issueComments 4635August 1984Indicated by a sideline in the margin Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 14:28:21 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5766-5:1981 BSI 12-1999i Contents Page Cooperating organizationsInside front cover National f
10、orewordii 1Scope and field of application1 2Principle1 3Reagents1 4Apparatus1 5Procedure1 6Expression of results2 7Test report2 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 14:28:21 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5766-5:1981 ii BSI 1
11、2-1999 National foreword This Part of BS 5766 has been prepared under the direction of the Food and Agriculture Standards Committee and is identical with ISO 6495:1980 “Animal feeding stuffs Determination of water-soluble chlorides content” published by the International Organization for Standardiza
12、tion (ISO). In the UK, animal feeding stuffs are controlled by legislation. This Part of BS 5766 is technically equivalent to the method given in The Feeding Stuffs (Sampling and Analysis) Regulations 1982. Terminology and conventions. The text of the International Standard has been accepted as suit
13、able for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is especially drawn to the following. Wherever the words “International Standard” appear, referring to this standard, they should b
14、e read as “British Standard”. The comma has been used throughout as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. Additional information. With reference to clause 3, water complying with the requirements of BS 3978 “Water for
15、 laboratory use” is suitable. NOTEWith reference to sampling and the preparation of test samples, attention is drawn to The Feeding Stuffs (Sampling and Analysis) Regulations 1982 which provide guidance and which are to be followed for legislative purposes. A British Standard does not purport to inc
16、lude all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, page
17、s i and ii, pages 1 and 2, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 14:28:21 GMT
18、+00:00 2006, Uncontrolled Copy, (c) BSI BS 5766-5:1981 BSI 12-19991 1 Scope and field of application This International Standard specifies a method for the determination of the water-soluble chlorides content, expressed as sodium chloride, of animal feeding stuffs. It is applicable to all animal fee
19、ding stuffs. 2 Principle Dissolution in water of the chlorides present in a test portion. Clarification of the solution if the product contains organic matter. Slight acidification with nitric acid and precipitation of the chlorides as silver chloride by means of standard volumetric silver nitrate s
20、olution. Titration of the excess silver nitrate with standard volumetric ammonium or potassium thiocyanate solution. 3 Reagents All reagents shall be of recognized analytical quality. Distilled water or water of at least equivalent purity shall be used. 3.1 Acetone 3.2 n-Hexane 3.3 Nitric acid, 20 1
21、,38 g/ml. 3.4 Activated carbon, free from chlorides and not capable of adsorbing chlorides. 3.5 Ammonium iron(III) sulphate, saturated solution. 3.6 Carrez I solution Dissolve in water, 21,9 g of zinc acetate dihydrate Zn(CH3COO)2.2H2O and add 3 ml of glacial acetic acid. Make up to 100 ml with wate
22、r. 3.7 Carrez II solution Dissolve in water, 10,6 g of potassium hexacyanoferrate(II) potassium ferrocyanide trihydrate K4Fe(CN)6.3H2O. Make up to 100 ml with water. 3.8 Ammonium or potassium thiocyanate, standard volumetric solution, c(NH4SCN) or c(KSCN) = 0,1 mol/l1). 3.9 Silver nitrate, standard
23、volumetric solution, c(AgNO3) = 0,1 mol/l1). 4 Apparatus Usual laboratory equipment, and in particular. 4.1 Rotary shaker, having a frequency of rotation of approximately 35 to 40 min1. 4.2 One-mark volumetric flasks, of capacities 200 and 500 ml. 4.3 Pipettes, of appropriate capacity. 4.4 Burettes
24、4.5 Analytical balance 5 Procedure 5.1 Test portion and preparation of the test solution According to the nature of the sample, take a test portion and prepare the test solution as specified in 5.1.1, 5.1.2 or 5.1.3. 5.1.1 Samples free from organic matter Weigh, to the nearest 1 mg, a test portion o
25、f not more than 10 g presumed to contain not more than 3 g of chlorides. Place with 400 ml of water in a 500 ml volumetric flask (4.2) at approximately 20 C. Mix for 30 min in the rotary shaker (4.1), make up to the mark with water, mix and filter. 5.1.2 Samples containing organic matter (excluding
26、the products listed in 5.1.3) Weigh, to the nearest 1 mg, a test portion of approximately 5 g and place it with 1 g of the activated carbon (3.4) in a 500 ml volumetric flask (4.2). Add 400 ml of water at approximately 20 C, and 5 ml of the Carrez I solution (3.6), stir, then add 5 ml of the Carrez
27、II solution (3.7). Mix for 30 min in the rotary shaker (4.1), make up to the mark with water, mix and filter. 5.1.3 Cooked feeding stuffs, flax cakes and flour, products rich in flax flour and other products rich in mucilage or in colloidal substances (for example dextrinated starch) Proceed as spec
28、ified in 5.1.2 but do not filter. Decant (if necessary, centrifuge), remove 100 ml of the supernatant liquid and transfer to a 200 ml volumetric flask (4.2). Mix with acetone (3.1), make up to the mark with the same solvent, mix and filter. 1) Hitherto expressed as “0,1 N standard volumetric solutio
29、n”. Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 14:28:21 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5766-5:1981 2 BSI 12-1999 5.2 Titration By means of a pipette (4.3), transfer to a conical flask an aliquot portion of 25 to 100 ml of the filtrate (according to the expected chlorides c
30、ontent) obtained as specified in 5.1.1, 5.1.2 or 5.1.3. The aliquot portion shall not contain more than 150 mg of chlorine (Cl). Make up, if necessary, to a volume of not less than 50 ml with water, add 5 ml of the nitric acid (3.3), 2 ml of the saturated ammonium iron(III) sulphate solution (3.5) a
31、nd 2 drops of the ammonium or potassium thiocyanate solution (3.8) from a burette (4.4) filled to the zero mark (the remainder of the solution is to be used afterwards for titration of the excess silver nitrate). Add from a burette (4.4), the silver nitrate solution (3.9) until an excess of 5 ml is
32、obtained. Shake vigorously to coagulate the precipitate. If necessary, 5 ml of n-hexane (3.2) may be added to assist coagulation. Titrate the excess silver nitrate with the ammonium or potassium thiocyanate solution (3.8) until a reddish-brown, tint persisting for at least 30 s, develops. 5.3 Blank
33、test Carry out a blank test in parallel with the determination, using the same procedure and the same reagents, but omitting the test portion. 5.4 Number of determinations Carry out two determinations on test portions taken from the same test sample. 6 Expression of results 6.1 Method of calculation
34、 and formulae 6.1.1 Samples treated in accordance with 5.1.1 and 5.1.2 The water-soluble chlorides content, expressed as sodium chloride as a percentage by mass, is equal to 6.1.2 Cooked feeding stuffs, flax cakes and flour, products rich in flax flour and other products rich in mucilage or in collo
35、idal substances The water-soluble chlorides content, expressed as sodium chloride as a percentage by mass, is equal to 6.1.3 In the preceding formulae (6.1.1 and 6.1.2): c1is the exact concentration of the silver nitrate solution (3.9); c2is the exact concentration of the ammonium or potassium thioc
36、yanate solution (3.8); Vis the volume, in millitres, of the aliquot portion of filtrate taken (see 5.2); V1is the volume, in millitres, of the silver nitrate solution added in the determination; V1is the volume, in millitres, of the silver nitrate solution added in the blank test; V2is the volume, i
37、n millilitres, of the ammonium or potassium thiocyanate solution used in the determination; V2is the volume, in millilitres, of the ammonium or potassium thiocyanate solution used in the blank test; mis the mass, in grams, of the test portion. 6.1.4 Express the result to the nearest: 0,05 % (m/m) so
38、dium chloride for sodium chloride contents less than 1 % (m/m); 0,1 % (m/m) sodium chloride for sodium chloride contents greater than or equal to 1 % (m/m). 6.2 Repeatability The difference between the results of two determinations carried out in rapid succession by the same analyst shall not exceed
39、: 0,05 (absolute value) for sodium chloride contents less than 1 % (m/m); 5 % (relative value) of the mean value for sodium chloride contents greater than 1 % (m/m). 7 Test report The test report shall show the method used and the result obtained. It shall also mention any operating conditions not s
40、pecified in this International Standard, or regarded as optional, as well as any circumstances that may have influenced the result. The report shall include all details necessary for complete identification of the sample. Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 14:28:21 GMT+00:00 2006
41、, Uncontrolled Copy, (c) BSI BS 5766-5:1981 BSI 12-1999 Publications referred to See national foreword. Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 14:28:21 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5766-5: 1981 ISO 6495:1980 BSI 389 Chiswick High Road London W4 4AL BSI British Standa
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