1、BRITISH STANDARD CONFIRMED APRIL1993 BS684-1.9: 1976 Methods of analysis of Fats and fatty oils Part1: Physical methods Section1.9: Determination of water-insoluble solvents IMPORTANT NOTE. It is essential that this Section be read in conjunction with the information in the “General introduction” to
2、 BS684, which is published separately. UDC 665.1.014:543:66.061:543.869BS684-1.9:1976 This BritishStandard, having been prepared under the directionof the Oils and FatsStandards Committee, waspublished under the authorityof the Executive Board on 29 October1976 BSI12-1999 The following BSI reference
3、s relate to the work on this standard: Committee referenceOFC/24 Draft for comment74/50396DC ISBN 0 580 09475 8 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 Briti
4、sh Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to3 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be
5、indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date of issue CommentsBS684-1.9:1976 BSI 12-1999 i Contents Page 0 Scope 1 1 Method 1. Determination of content of solvents lighter than water 1 1.1 Field of application 1 1.2 Reference 1 1.3 Pri
6、nciple 1 1.4 Apparatus 1 1.5 Sampling and preparation of sample for analysis 1 1.6 Procedure 1 1.7 Expression of results 1 1.8 Test report 1 2 Method 2. For determination of content of solvents heavier than water 2 2.1 Field of application 2 2.2 Reference 2 2.3 Principle 2 2.4 Apparatus 2 2.5 Sampli
7、ng and preparation of sample for analysis 3 2.6 Procedure 3 2.7 Expression of results 3 2.8 Test report 3 Figure 1 Condenser and spray tube 2 Figure 2 Receiver type2 showing alternative connections to distillation vessel 2 Figure 3 Distillation apparatus 3ii blankBS684-1.9:1976 BSI 12-1999 1 0 Scope
8、 This Section describes two methods for the determination of water-insoluble solvents present in excess of0.5ml in100g of fat. Method1 is suitable for the determination of solvents which are lighter than water and is based on the Institute of Petroleum methodIP23/68. Method2 is suitable for the dete
9、rmination of solvents which are heavier than water. Both methods are applicable to most animal and vegetable fats. 1 Method1. Determination of content of solvents lighter than water 1.1 Field of application The method described is suitable for the determination of the content of water-insoluble solv
10、ents, present in excess of0.5ml in100g of fat, which are lighter than water. 1.2 Reference The following standards publication is referred to in this method: BS756, Dean and Stark apparatus. 1.3 Principle Solvent is removed from the sample by steam-distillation and after cooling, the volume of conde
11、nsed solvent is determined volumetrically. 1.4 Apparatus Use the following items of apparatus as described in BS756 and see also BS684: General introduction. 1.4.1 Flask, round-bottomed,1litre capacity, with a short neck. 1.4.2 Condenser, of the glass water-cooled reflux type, and spray tube (see Fi
12、gure 1). 1.4.3 Receiver, type2, of3,5 or12.5ml capacity (seeFigure 2). 1.4.4 Source of heat, either a gas burner, preferably of the Meker type,25mm in diameter, with an orifice so that a narrow flame coming to a point about100mm above the top of the burner can be obtained, or an electric heating man
13、tle. NOTEIt is important that the receiver and condenser should be thoroughly clean. They should, therefore, be treated with a mixture of potassium dichromate and sulphuric acid or other suitable cleaning agent prior to use. 1.5 Sampling and preparation of sample for analysis See BS684: General intr
14、oduction. 1.6 Procedure Mix the sample of fat thoroughly and weigh25g into the flask. Add approximately500ml of water to the flask and assemble the apparatus after filling the receiver with water. Heat the flask, adjusting the rate of heating so that refluxing starts within7min to10min, the water be
15、ing at room temperature initially. Heat at such a rate that boiling is continuous and vigorous enough to prevent the fat from forming, even momentarily, a continuous film on top of the water. NOTEBumping with a tendency to froth over is often experienced with dirty fats and may be prevented in sever
16、al ways, e.g.by the addition of pumice, pieces of broken glass or steel wool, or by the addition of about5ml of concentrated hydrochloric acid. Read the volume of solvent in the receiver after intervals of5,15 and30min from the instant that refluxing starts, and subsequently every15min until the vol
17、ume of solvent increases by not more than0.1ml in any subsequent15min period. Turn off the source of heat. Let the distillate stand for at least15min to allow it to separate and to cool to approximately room temperature, and then record the volume of the solvent. 1.7 Expression of results Express th
18、e content of water-insoluble solvent as a percentage volume/mass (i.e.millilitres per100g). Calculate the content of water-insoluble solvent using the formula: 1.8 Test report See the general instructions and recommendations given in BS684: General introduction. where V is final volume of solvent (i
19、nml) M is mass of the sample taken (ing) 100V M -BS684-1.9:1976 2 BSI 12-1999 2 Method2. For determination of content of solvents heavier than water 2.1 Field of application The method described is suitable for the determination of the content of water-insoluble solvents, present in excess of0.5ml i
20、n100g of fat, that are heavier than water. 2.2 Reference See1.2. 2.3 Principle See1.3. 2.4 Apparatus Use the following items of apparatus as described in BS756, See also BS684: General introduction and Figure 3. 2.4.1 Flask, round-bottomed,1litre capacity, with a short neck. 2.4.2 Condenser, of the
21、glass water-cooled reflux type, and spray tube (see Figure 1). Figure 1 Condenser and spray tube Figure 2 Receiver type2 showing alternative connections to distillation vesselBS684-1.9:1976 BSI 12-1999 3 2.4.3 Receiver, type1, of the appropriate capacity (seeFigure 3). 2.4.4 Source of heat, either a
22、n oil bath or an electric heating mantle. NOTEIt is important that the receiver and condenser should be thoroughly clean. They should, therefore, be treated with a mixture of potassium dichromate and sulphuric acid or other suitable cleaning agent prior to use. 2.5 Sampling and preparation of sample
23、 for analysis See1.5. 2.6 Procedure Mix the sample of fat thoroughly and weigh25g into the flask. Add approximately500ml of water to the flask and assemble the apparatus after filling the receiver with water. Heat the flask and continue heating at such a rate that boiling is continuous and vigorous
24、enough to prevent the fat from forming, even momentarily, a continuous film on top of the water. NOTEBumping with a tendency to froth over is often experienced with dirty fats and may be prevented in several ways, e.g.by the addition of pumice, pieces of broken glass or steel wool, or by the additio
25、n of about5ml of concentrated hydrochloric acid. Read the volume of solvent in the receiver after intervals of5,15 and30min from the instant that refluxing starts, and subsequently every15min until the volume of solvent increases by not more than0.1ml in any subsequent15min period. Turn off the sour
26、ce of heat and detach any globules of solvent that may remain on the condenser wall by means of a spray of water delivered through the spray tube. Let the distillate stand for at least15min to allow it to separate and to cool to approximately room temperature. Record the volume of the solvent. 2.7 E
27、xpression of results See1.7. 2.8 Test report See the general instructions and recommendations given in BS684: General introduction. Figure 3 Distillation apparatusBS684-1.9: 1976 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible
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