1、BRITISH STANDARD BS 5766-8: 1999 ISO 6496:1999 Methods for analysis of animal feeding stuffs Part 8: Determination of moisture and other volatile matter content ICS 65.120BS5766-8:1999 This British Standard, having been prepared under the directionof the Consumer Products and Services Sector Committ
2、ee, was published underthe authority of the Standards Committee and comesinto effect on 15October1999 BSI 04-2000 ISBN 0 580 32947 X National foreword This British Standard reproduces verbatim ISO 6496:1999 and implements it as the UK national standard. It supersedes BS 5766-8:1983 which is withdraw
3、n. The UK participation in its preparation was entrusted to Technical Committee AW/10, Animal feeding stuffs, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for chang
4、e, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or Eur
5、opean publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the nec
6、essary 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, pages i and ii, theI
7、SO title page, pages ii to iv, pages 1 to 6 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. Amendments issued since publication Amd. No. Date CommentsBS5766-8:1999
8、 BSI 04-2000 i Contents Page National foreword Inside front cover Foreword iii Text of ISO 6496 1ii blankBS5766-8:1999 ii BSI 04-2000 Contents Page Foreword iii 1 Scope 1 2 Normative references 1 3 Term and definition 1 4 Principle 1 5 Apparatus and materials 1 6 Sampling 2 7 Preparation of test sam
9、ple 2 8 Procedure 2 9 Expression of results 3 10 Precision 4 11 Test report 4 Annex A (informative) Results of interlaboratory test 5 Bibliography 6 Table 1 Repeatability limit (r) and reproducibility limit (R) 4 Table A.1 Statistical results of the interlaboratory test 5BS5766-8:1999 BSI 04-2000 ii
10、i 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
11、 technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matte
12、rs of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part3. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard
13、requires approval by at least75% of the member bodies casting a vote. International Standard ISO 6496 was prepared by Technical Committee ISO/TC 34, Agricultural food products, Subcommittee SC 10, Animal feeding stuffs. This second edition replaces the first edition (ISO 6496:1983), which has been t
14、echnically revised. Annex A of this International Standard is for information only.iv blankBS5766-8:1999 BSI 04-2000 1 1 Scope This International Standard specifies a method for the determination of the moisture and other volatile matter content of animal feeding stuffs. The method is applicable to
15、animal feeding stuffs with the exception of: a) milk products; b) mineral substances; c) mixtures containing a considerable amount of milk products or mineral substances, for example milk replacers; d) animal feeding stuffs containing humectants (e.g. propylene glycol); e) the following simple anima
16、l feeding stuffs: animal and vegetable fats and oils (for which method A specified in ISO662 1 is applicable); oilseeds (for which a method is specified in ISO6652); oilseed residues (for which a method is specified in ISO7713); cereals, except maize, and cereal products (for which a method is speci
17、fied in ISO7124); maize (for which the reference method specified in ISO65405 is applicable). 2 Normative reference The following normative document contains provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amend
18、ments to, or revisions of, such publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. For undated references, the latest edition of th
19、e normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 6498, Animal feeding stuffs Preparation of test samples. 3 Term and definition For the purposes of this International Standard, the following term and definition apply.
20、 3.1 moisture and other volatile matter content mass fraction of substances lost on drying the sample by the procedure specified in this International Standard NOTEThe moisture and other volatile matter content is expressed as a mass fraction in percent formerly given as% (m/m). 4 Principle The loss
21、 of mass of a test portion of the sample on drying is determined under specified conditions depending on the nature of the sample. 5 Apparatus and materials Usual laboratory apparatus and materials and, in particular, the following. 5.1 Analytical balance, capable of weighing to the nearest1mg. 5.2
22、Container, of non-corrodible metal or glass, provided with a sufficiently tight-fitting lid, and having a surface allowing the test portion to be spread to about0,3g/cm 2 . 5.3 Electrically heated oven, well ventilated, capable of being maintained at a temperature of103 C 2 C. 5.4 Electrically heate
23、d vacuum oven, capable of being maintained at a temperature of80 C 2 C, and capable of producing a pressure below13kPa. It shall be provided with a thermostat and vacuum pump, and either a device for the introduction of dried air, or a device containing calcium oxide (CaO) as desiccant(300g CaO for2
24、0samples).BS5766-8:1999 2 BSI 04-2000 5.5 Desiccator, provided with an efficient desiccant. 5.6 Sand, acid-washed. 6 Sampling Sampling is not part of the method specified in this International Standard. A recommended sampling method is given in ISO64976. It is important that the laboratory receive a
25、 sample which is truly representative and has not been damaged or changed during transport or storage. Store the sample in such a way that deterioration and change in composition are minimized. 7 Preparation of test sample Prepare the test sample in accordance with ISO6498. 8 Procedure 8.1 Test port
26、ion 8.1.1 Feeding stuffs in liquid or paste form, and feeding stuffs predominantly composed of oils and fats Place a thin layer of sand(5.6) and a glass rod into a container(5.2). Dry the container with its contents and lid in the oven (5.3) set at103 C for30min 1min. Place the lid on the container,
27、 remove from the oven and allow to cool to ambient temperature in the desiccator (5.5). Weigh the container with its contents and lid to the nearest1mg. Into the container, weigh, to the nearest1mg, about10g of the prepared test sample (clause7). Using the glass rod, mix thoroughly with the sand. Le
28、ave the glass rod in the container. Proceed in accordance with8.2. 8.1.2 Other feeding stuffs Dry a container (5.2) with its lid in the oven (5.3) set at103 C for30min1min. Remove from the oven and allow to cool to ambient temperature in the desiccator(5.5). Weigh the container with its lid to the n
29、earest1mg. Into the container, weigh, to the nearest1mg, about5g of the prepared test sample (clause7) and spread evenly. 8.2 Determination Place the container, with its lid beneath or beside it, in the oven(5.3) set at103 C. It is recommended that not more than one container per litre of oven volum
30、e be placed in the oven. Leave to dry for 4 h 0,1h after the oven temperature has returned to103 C. Place the lid on the container, remove from the oven, allow to cool to ambient temperature in the desiccator(5.5) and weigh to the nearest1mg. Feeding stuffs consisting mainly of oils or fats shall be
31、 dried for another30min 1min in the oven(5.3) set at 103 C. The change in mass between the two weighings shall not exceed0,1% of the mass of the test portion. If the change in mass is more than0,1% of the mass of the test portion, discard the result and repeat the procedure. If the change in mass is
32、 again more than0,1% of the mass of the test portion, proceed in accordance with8.3. 8.3 Check test In order to check whether during drying of the test portion an unacceptable change in mass occurs as a result of chemical reactions (for example Maillard reactions), proceed as follows. Dry the contai
33、ner and test portion again in the oven(5.3) set at 103 C for2h 0,1h. Allow to cool to ambient temperature in the desiccator (5.5) and weigh to the nearest1mg. If the change in mass during this second drying period is more than0,2% of the mass of the test portion, chemical reactions may have occurred
34、. In this case, discard the result and apply the procedure specified in8.4. NOTEThe criterion of 0,2% of the mass of the test portion should not be confused with the repeatability limit of 0,2% defined in10.2. The latter concerns the absolute difference between two independent single test results ob
35、tained under repeatability conditions. The former is based on the difference between two weighings of the same test portion before and after an extra period of heating in order to check whether an unacceptable change in mass has occurred.BS5766-8:1999 BSI 04-2000 3 8.4 Samples giving unacceptable ch
36、ange in mass Take the test portion in accordance with8.1. Place the container, with its lid beneath or beside it, in the vacuum oven (5.4) set at80 C. Reduce the pressure to about13kPa and dry the sample at this pressure, either while admitting dried air, or in the presence of the desiccant (see5.4)
37、. In the latter case, disconnect the vacuum pump after the specified pressure has been reached and ensure that this pressure is maintained throughout the drying period. Heat the sample for4h 0,1h after the oven temperature has returned to80 C. Return the oven pressure carefully to atmospheric pressu
38、re. Open the oven, immediately place the lid on the container, remove from the oven, allow to cool to ambient temperature in the desiccator (5.5) and weigh to the nearest1mg. Dry for additional periods of30min 1min in the vacuum oven set at80 C and weigh until the change in mass between two consecut
39、ive weighings does not exceed0,2% of the mass of the test portion. 8.5 Number of determinations Carry out two determinations on test portions taken from the same test sample. 9 Expression of results 9.1 Determination without preliminary conditioning Calculate the moisture and other volatile matter c
40、ontent of the test sample, w 1 , in percent, by the equation: where 9.2 Determination with preliminary conditioning NOTEFor samples which are difficult to crush, see ISO6498. 9.2.1 Samples with moisture content more than17% and fat content less than 120g/kg, which need only preliminary drying Calcul
41、ate the moisture and other volatile matter content of the test sample, w 2 , in percent, by the equation: where m 3 is the mass, in grams, of the test portion; m 4 is the mass, in grams, of the container with lid including, if appropriate, sand and glass rod; m 5 is the mass, in grams, of the contai
42、ner with lid and dried test portion including, if appropriate, sand and glass rod. m 0 is the mass, in grams, of the test sample; m 1 is the mass, in grams, of the test sample after extraction and/or drying and conditioning in ambient air; m 3 is the mass, in grams, of the test portion; m 4 is the m
43、ass, in grams, of the container with lid including, if appropriate, sand and glass rod; m 5 is the mass, in grams, of the container with lid and dried test portion including, if appropriate, sand and glass rod.BS5766-8:1999 4 BSI 04-2000 9.2.2 Samples with high fat content and low moisture content,
44、which need only preliminary defatting, and samples with high fat content and high moisture content, which need preliminary drying followed by preliminary defatting Calculate the moisture and other volatile matter content of the test sample, w 3 , in percent, by the equation: where m 2is the mass, in
45、 grams, of the fat extracted from the test sample (see ISO6498). For the explanation of the other symbols, see9.2.1. 9.3 Results Take as the result the arithmetic mean of the two intermediate test results (8.5), provided that the absolute difference between the two results does not exceed 0,2%. Repe
46、at the procedure if the difference exceeds0,2%. Express the result to the nearest0,1%. 10 Precision 10.1 Interlaboratory test Details of an interlaboratory test on the precision of the method are summarized inAnnex A. The values derived from this interlaboratory test may not be applicable to concent
47、ration ranges and matrices others than those given. 10.2 Repeatability The absolute difference between two independent single test results, obtained using the same method on identical test material in the same laboratory by the same operator using the same equipment within a short interval of time,
48、will in not more than5% of cases exceed the repeatability limit r given in or derived fromTable 1. Table 1 Repeatability limit (r) and reproducibility limit (R) 10.3 Reproducibility The absolute difference between two single test results, obtained using the same method on identical test material in
49、different laboratories with different operators using different equipment, will in not more than5% of cases exceed the reproducibility limit R given in or derived fromTable 1. 11 Test report The test report shall specify: all information necessary for the complete identification of the sample; the sampling method used, if known; the test method used, with reference to this International Standard; all operating details not specified in this International Standard, or regarded as optional, together with det
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