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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 water content Entrainment m
2、ethod 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 665.1.014:543.812 Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:16:07 GMT+00:00 2006, Uncontrolled Copy, (c) BSI
3、 BS 684-1.16:1981 This British Standard, having been prepared under the direction of the Oils and Fats Standards Committee, was published under the authority of the Executive Board and comes into effect on 30 January 1981 BSI 09-1999 First published October 1976 First revision January 1981 The follo
4、wing BSI references relate to the work on this standard: Committee reference OFC/3 Draft for comment 79/50935 DC ISBN 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”, publishe
5、d by the International Organization for Standardization (ISO) and supersedes BS 684-1.16:1976, which is therefore withdrawn. 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 c
6、onventions. The text of the International Standard has been approved as suitable 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. The comma has bee
7、n 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. Wherever the words “International Standard” appear, referring to this standard, they should be read as “British Standard”. Additional information. In 8.3, par
8、agraph 4, there is reference to the use of a brush or a wire. The use of a brush may be unsuitable and it is recommended 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 applic
9、ation. 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, pages 1 and 2, an inside back cover and a back cover. This standard has been updated (see copyright date
10、) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Cross-reference International StandardCorresponding British Standard ISO 661:1980BS 684 Methods of analysis of fats and fatty oils Part 0:1982 General introduction (Appendix B) (Ident
11、ical) Amendments issued since publication Amd. No.Date of issueComments 4148December 1982 Indicated by a sideline in the margin Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:16:07 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 684-1.16:1981 BSI 09-1999i Contents Page National forewordInsi
12、de front cover 1Scope and field of application1 2Reference1 3Definition1 4Principle1 5Reagent1 6Apparatus1 7Sampling1 8Procedure1 9Expression of results2 10Test report2 Figure Distillation apparatus2 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:
13、16:07 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:16:07 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 684-1.16:1981 BSI 09-19991 1 Scope and field of application This International Standard specifies a method for the determination, by
14、 entrainment, of the water content of animal or vegetable fats or oils. The method is applicable to products having 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
15、entrained and collected under the conditions specified in this International Standard, and expressed as a percentage 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 vo
16、lume of water collected. 5 Reagent Xylene, commercial quality, containing isomers or mixtures of isomers in varying 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 m
17、eans of ground glass joints: 6.2.1 Flask, short-necked, of capacity at least 500 ml. 6.2.2 Reflux condenser 6.2.3 Receiver, having a graduated tube of capacity 5 ml, 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 th
18、e receiver and the inside of the condenser tube, thoroughly clean the apparatus by suitable means, and wash successively 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 r
19、epresentative sample of at least 250 g. 8 Procedure 8.1 Preparation of the test sample Prepare the test sample in accordance 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 Determi
20、nation Add to the flask containing the test portion (8.2), 100 to 300 ml (according to the mass of the test portion) 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 appara
21、tus (6.2). Heat the flask gradually until the xylene boils; the water carried over by the xylene is collected in the 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 c
22、ompletely and until there is no emulsified zone. If drops of water adhere to the tube or the condenser, use a long-handled 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 paraff
23、in is recommended. 8.4 Number of determinations Carry out two determinations on test portions taken from the same test sample. Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:16:07 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 684-1.16:1981 2 BSI 09-1999 9 Expression of results 9.1 Method
24、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 arithmetic mean of the two determinations, provided that the requirement for re
25、peatability (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 not exceed 0,1 ml of water. NOTEThe repeatability expressed as a percentage
26、 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 or regarded as optional, as well as any circumstances that may have influe
27、nced 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 test portion. V100 m - - Figure Distillation apparatus Licensed Copy: sheffie
28、ldun sheffieldun, na, Wed Dec 06 13:16:07 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 684-1.16:1981 BSI 09-1999 Publications referred to See national foreword. Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:16:07 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 684-1.16: 1981 ISO 934:1980
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