BS 684-1 16-1981 Methods of analysis of fats and fatty oils - Physical methods - Determination of water content entrainment method《脂肪和油脂分析方法 第1部分 物理法 第16节 含水量测定 夹带法》.pdf

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1、BRITISH STANDARD BS 684-1.16: 1981 ISO 934:1980 Incorporating Amendment No. 1 Methods of analysis of Fats and fatty oils Part 1: Physical methods Section 1.16 Determination of water content: entrainment method ISO title:Animal and vegetable fats and oils Determination of watercontent Entrainment met

2、hod IMPORTANT NOTE. It is essential that this Section be read in conjunction with the information in the “General introduction” to BS 684, which is published separately. UDC 665.1.014:543.812BS684-1.16:1981 This British Standard, having been prepared under the directionof the Oils and Fats Standards

3、 Committee, was published under the authority ofthe Executive Boardand comesinto effect on 30 January 1981 BSI 09-1999 First published October 1976 First revision January 1981 The following BSI references relate to the work on this standard: Committee reference OFC/3 Draft for comment 79/50935 DC IS

4、BN 0 580 11881 9 National foreword This Section of BS 684 is identical with ISO 934:1980 “Animal and vegetable fats and oils Determination of water content Entrainment method”, published by the International Organization for Standardization (ISO) and supersedes BS 684-1.16:1976, which is therefore w

5、ithdrawn. Method 2 (intended for use when an emulsion of water and solvent is formed) of the 1976 edition is not included in this revision as it is no longer required. Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a British Stand

6、ard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is especially drawn to the following. The comma has been used throughout as a decimal marker. In British Standards it is current practice to use a full point on the basel

7、ine as the decimal marker. Wherever the words “International Standard” appear, referring to this standard, they should be read as “British Standard”. Additional information. In 8.3, paragraph 4, there is reference to the use of a brush or a wire. The use of a brush may be unsuitable and it is recomm

8、ended that a wire be used. A British Standard does not purport to include 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 pag

9、es This document comprises a front cover, an inside front cover, pages i and ii, pages1 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.

10、 Cross-reference International Standard Corresponding British Standard ISO 661:1980 BS 684 Methods of analysis of fats and fatty oils Part0:1982 General introduction (Appendix B) (Identical) Amendments issued since publication Amd. No. Date of issue Comments 4148 December 1982 Indicated by a sidelin

11、e in the marginBS684-1.16:1981 BSI 09-1999 i Contents Page National foreword Inside front cover 1 Scope and field of application 1 2 Reference 1 3 Definition 1 4 Principle 1 5 Reagent 1 6 Apparatus 1 7 Sampling 1 8 Procedure 1 9 Expression of results 2 10 Test report 2 Figure Distillation apparatus

12、2 Publications referred to Inside back coverii blankBS684-1.16:1981 BSI 09-1999 1 1 Scope and field of application This International Standard specifies a method for the determination, by entrainment, of the water content of animal or vegetable fats or oils. The method is applicable to products havi

13、ng water contents greater than or equal to 0,5 % (m/m). 2 Reference ISO 661, Animal and vegetable fats and oils Preparation of test sample. 3 Definition water content the amount of water entrained and collected under the conditions specified in this International Standard, and expressed as a percent

14、age by mass 4 Principle Entrainment of the water present in a test portion, by azeotropic distillation with the aid of an organic liquid not miscible with water, and measurement of the volume of water collected. 5 Reagent Xylene, commercial quality, containing isomers or mixtures of isomers in varyi

15、ng proportions. 6 Apparatus Usual laboratory apparatus and in particular: 6.1 Balance 6.2 Distillation apparatus (see the Figure), comprising the following components fitted together by means of ground glass joints: 6.2.1 Flask, short-necked, of capacity at least 500 ml. 6.2.2 Reflux condenser 6.2.3

16、 Receiver, having a graduated tube of capacity5ml, interposed between the flask (6.2.1) and the condenser (6.2.2). NOTEIn order to remove all traces of fat from the graduated tube of the receiver and the inside of the condenser tube, thoroughly clean the apparatus by suitable means, and wash success

17、ively with distilled water and with acetone. Then dry the apparatus in a current of air without heating. 6.3 Boiling aid, for example pumice-stone fragments. 7 Sampling Proceed from a representative sample of at least 250 g. 8 Procedure 8.1 Preparation of the test sample Prepare the test sample in a

18、ccordance with ISO 661. 8.2 Test portion Weigh, to the nearest 0,01 g, 20 to 100 g of the test sample (8.1), according to the expected water content, into the flask (6.2.1). 8.3 Determination Add to the flask containing the test portion (8.2), 100 to 300 ml (according to the mass ofthe test portion)

19、 of the xylene (clause 5) and a boiling aid (6.3). The volume of test portion and xylene together shall not exceed one-half of the volume of the flask. Assemble the distillation apparatus (6.2). Heat the flask gradually until the xylene boils; the water carried over by the xylene is collected in the

20、 graduated tube of the receiver (6.2.3). When the distilled solvent is clear and no more water separates from it, stop heating and allow to stand long enough for the water to collect completely and until there is no emulsified zone. If drops of water adhere to the tube or the condenser, use a long-h

21、andled brush or a wire to combine them with the water collected in the tube. Should froth form during boiling of the xylene, the addition of 1 to 2 g of dry oleic acid or liquid paraffin is recommended. 8.4 Number of determinations Carry out two determinations on test portions taken from the same te

22、st sample.BS684-1.16:1981 2 BSI 09-1999 9 Expression of results 9.1 Method of calculation and formula The water content, expressed as a percentage by mass, is equal to NOTEIt is assumed that the density of water is exactly 1 g/ml within the precision of the determination. Take as the result the arit

23、hmetic mean of the two determinations, provided that the requirement for repeatability (see 9.2) is satisfied. 9.2 Repeatability The difference between the results of two determinations carried out simultaneously or in rapid succession by the same analyst, using the same mass of test portion, shall

24、not exceed 0,1 ml of water. NOTEThe repeatability expressed as a percentage of water depends on the mass of the test portion. 10 Test report The test report shall show the method used and the result obtained. It shall also mention any operating conditions not specified in this International Standard

25、 or regarded as optional, as well as any circumstances that may have influenced the result. The report shall include all details required for the complete identification of the sample. where V is the volume, in millilitres, of water collected in the graduated tube; m is the mass, in grams, of the te

26、st portion. V 100 m - Figure Distillation apparatusBS684-1.16:1981 BSI 09-1999 Publications referred to See national foreword.BS684-1.16: 1981 ISO934:1980 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishSta

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