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1、BRITISH STANDARD BS EN ISO 8892:1995 BS 4325-10: 1995 Oilseed residues Determination of total residual hexane The European Standard EN ISO 8892:1995 has the status of a British Standard Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 19 13:57:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN I
2、SO 8892:1995 This British Standard, having been prepared under the direction of the Consumer Products and Services Sector Board, was published under the authority of the Standards Board and comes into effect on 15 August 1995 BSI 10-1999 The following BSI references relate to the work on this standa
3、rd: Committee reference AW/2 Draft announced in BSI News February 1994 ISBN 0 580 24013 4 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee AW/2, Oilseeds and residues, upon which the following bodies were represented: Brit
4、ish Food Manufacturing Industries Research Association Department of Trade and Industry (Laboratory of the Government Chemist) FOSFA International Grain and Feed Trade Association Institute of Biology Ministry of Agriculture, Fisheries and Food National Farmers Union National Institute of Agricultur
5、al Botany Royal Society of Chemistry Seed Crushers and Oil Processors Association Tropical Growers Association United Kingdom Agricultural Supply Trade Association Ltd. Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 19 13:57:29 GMT+00:00
6、2006, Uncontrolled Copy, (c) BSI BS EN ISO 8892:1995 BSI 10-1999i Contents Page Committees responsibleInside front cover National forewordii Foreword2 1Scope and field of application3 2Reference3 3Principle3 4Reagents and materials3 5Apparatus3 6Sampling and sample storage3 7Procedure3 8Expression o
7、f results4 9Precision4 10Test report4 Table Statistical results of interlaboratory tests5 List of referencesInside back cover Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 19 13:57:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 8892:1995 ii BSI 10-1999 National foreword This British S
8、tandard has been prepared by Technical Committee AW/2 and is the English language version of EN ISO 8892:1995 Oilseed residues Determination of total residual hexane, published by the European Committee for Standardization (CEN). It is identical with ISO 8892:1987 published by the International Orga
9、nization for Standardization (ISO) and in the preparation of which the UK played a full part. It supersedes BS 4325-10:1988 which is withdrawn and from which it differs in that the cross-references have been updated. A British Standard does not purport to include all the necessary provisions of a co
10、ntract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references Publication referred toCorresponding British Standard ISO 5500:1986BS 6606:1987 Methods for sampling oilsee
11、d residues ISO 5725:1986BS 5497 Precision of test methods Part 1:1987 Guide for the determination of repeatability and reproducibility for a standard test method by inter-laboratory tests Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN ISO title
12、page, pages 2 to 6, 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, Sun Nov 19 13:57:29 GMT+00:00
13、2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 8892 April 1995 ICS 67.200.20 Descriptors: Agricultural products, oilseeds, chemical analysis, determination of content, hexane English version Oilseed residues Determination of total residual hexane (ISO 8892:
14、1987) Tourteaux de graines olagineuses Dosage de lhexane rsiduaire total (ISO 8892:1987) lsaatrckstnde (Extraktionsschrot) Bestimmung des gesamten Resthexans (ISO 8892:1987) This European Standard was approved by CEN on 1995-01-05. CEN members are bound to comply with the CEN/CENELEC Internal Regula
15、tions which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This Eur
16、opean Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the nat
17、ional standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr N
18、ormung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1995 Copyright reserved to all CEN members Ref. No. EN ISO 8892:1995 E Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 19 13:57:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 8892:1995 BSI 10-1999 2 Foreword The text of the In
19、ternational Standard from ISO/TC 34, Agricultural food products, of the International Organization for Standardization (ISO) has been taken over as a European Standard by the Technical Committee CEN/TC 307, Oilseeds, vegetable and animal fats and oils and their by-products Methods of sampling and an
20、alysis. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 1995, and conflicting national standards shall be withdrawn at the latest by October 1995. According to the CEN/CENELEC Internal Reg
21、ulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom. Licensed Copy: sheffieldun sheffieldun, na, Su
22、n Nov 19 13:57:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 8892:1995 BSI 10-19993 1 Scope and field of application This International Standard specifies a method for the determination of the total amount of volatile hydrocarbons, referred to generally as hexane, remaining in oilseed residue
23、s after extraction with hydrocarbon-based solvents. 2 Reference ISO 5500, Oilseed residues Sampling. 3 Principle Desorption of hexane by heating at 110 C with water in a closed vessel, and determination of the hexane in the headspace by gas chromatography using capillary or packed columns. Expressio
24、n of the results as n-hexane. 4 Reagents and materials 4.1 Technical n-hexane or light petroleum, with a composition similar to that used in the industrial extraction of oilseeds, or failing that, n-hexane. 4.2 Carrier gas: hydrogen or nitrogen, helium, etc., dry and containing less than 10 mg/kg of
25、 oxygen. 4.3 Auxiliary gases Hydrogen, 99,9 % pure, containing no organic impurities. Air, containing no organic impurities. 5 Apparatus Usual laboratory apparatus and in particular 5.1 Gas chromatograph, with flame ionization detector and integrator and/or recorder, equipped with a glass capillary
26、column approximately 30 m long and 0,3 mm in diameter, coated with methylpolysiloxanes1) (film thickness 0,2 4m) or, failing this, a packed column at least 1,7 m long and 2 to 4 mm internal diameter, packed with acid-washed diatomaceous earth of particle size 150 to 180 4m2), and coated with methylp
27、olysiloxanes1). If a capillary column is used, the apparatus shall have a 1/100 input divider. 5.2 Electric oven, capable of being maintained at 110 C. 5.3 Gas syringe, graduated, of capacity 1 ml, preferably with a valve. 5.4 Penicillin-type flasks, of capacity 50 to 60 ml, all with the same volume
28、 to within 2 %. 5.5 Septa, inert to solvents, of approximately 3 mm thickness, of a material such as nitrile rubber (for example Perbunan), or butyl rubber with a PTFE or polychloroprene seam (for example Neoprene). NOTEEnsure that the septa used will produce a hermetic seal after crimping. 5.6 Meta
29、llic foil caps, for example of aluminium. 5.7 Crimping pliers 5.8 Liquid syringe, of capacity 10 4l. 6 Sampling and sample storage See ISO 5500. It is essential that loss of hexane from the sample be prevented. The laboratory sample shall fill a completely sealed container (preferably a crimped meta
30、l box) and shall be stored at 20 C or below (for example in a deep-freezer). Plastics containers shall not be used. The determination of residual hexane shall be carried out as soon as the container has been brought to room temperature and opened. 7 Procedure 7.1 Test portion Weigh, to the nearest 0
31、,1 g, 5 g of the laboratory sample into a flask (5.4). Add 2,5 ml of distilled water, seal the flask with a septum (5.5), cover with a foil cap (5.6) and crimp with the pliers (5.7). All these operations shall be performed rapidly. 7.2 Desorption of the hexane Place the flask in the oven (5.2), main
32、tained at 110 C, for 90 min. When this time has elapsed, remove the flask from the oven and leave to cool for 2 min, then agitate by inverting. NOTEIt is important to leave the flasks in the oven for the same length of time for each sample. 7.3 Analysis of the headspace by gas chromatography NOTEThe
33、 septa often have a very high mechanical resistance; if it is thought, therefore, that the needle of the gas syringe may be damaged by using it to perforate septa, perforate instead with a pin before taking the sample from the headspace. Reuse of septa is not recommended. 7.3.1 Setting of the appara
34、tus Injector and detector temperature: 120 C Oven temperature: 40 C Carrier gas pressure: 0,3 bar (30 kPa) 1) SE 30 is suitable. 2) Chromosorb WAW is suitable. Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 19 13:57:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 8892:1995 4 BSI 10-1999 7.
35、3.2 Test Using the gas syringe (5.3) previously heated to between 50 and 60 C, take exactly 0,5 ml of the gaseous phase and inject quickly into the chromatograph. 7.3.3 Calibration Three points, for example with 2, 5 and 10 4l of solvent, are usually sufficient for constructing the calibration graph
36、; they correspond to 264, 660 and 1 320 mg/kg of hexane if the test portion is 5 g of residue. Prepare a calibration series using flasks (5.4) of the same capacity as those used for the determination. Add to the flasks 6 ml of water3), followed immediately by various quantities of n-hexane (4.1), me
37、asured accurately with the aid of the syringe (5.8). Seal each flask with a septum (5.5), cover with a foil cap (5.6) and crimp with the pliers (5.7). Place the various flasks for the establishment of one calibration graph in the oven for 15 min at 110 C. At the end of this time, remove the flasks f
38、rom the oven and leave to cool for 2 min. With the gas syringe heated to between 50 and 60 C, take exactly 0,5 ml of the headspace and inject quickly into the chromatograph. 7.4 Number of determinations Carry out two determinations on the same laboratory sample. 8 Expression of results Construct the
39、 calibration graph by plotting the area of the solvent peak as a function of the mass of solvent introduced into the flask (1 4l corresponding to 660 4g). Determine the sum of the peak areas of the hexane and various hydrocarbons which usually make up the technical solvent (2-methyl pentane, 3-methy
40、l pentane, methylcyclopentane, cyclohexane, etc.). NOTEDo not include peaks due to oxidation products if present in significant amounts, but report these separately. Read off from the calibration graph the mass, m1, in micrograms, of hexane present in the flask. The total residual hexane content of
41、the residue, expressed in milligrams of hexane per kilogram, is equal to where m0 is the mass, in grams, of the test portion; m1 is the mass, in micrograms, of solvent present in the flask. Take as the result the arithmetic mean of the two determinations. 9 Precision Two interlaboratory tests organi
42、zed at the international level with 12 laboratories participating, each carrying out three determinations (No. 1), and 15 laboratories, each carrying out two determinations (No. 2), gave the statistical results (determined in accordance with ISO 5725) shown in the Table. 10 Test report The test repo
43、rt shall show the method used and the results obtained. It shall also mention any operating details not specified in this International Standard, or regarded as optional, together with details of any incidents likely to have influenced the results. The report shall include all the information necess
44、ary for the complete identification of the sample. 3) 5 g of hydrated residue per 2,5 ml of water occupies on average a volume of 6 ml. m1 m0 - - Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 19 13:57:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 8892:1995 BSI 10-19995 Table Statistical
45、 results of interlaboratory tests Results expressed in milligrams of hexane per kilogram SampleSoya residue Sunflower residue Colza (rape) residue Interlaboratory testNo. 2No. 1No. 1No. 2No. 1 Number of laboratories remaining after elimination of outliers 1511111510 Mean341400450452971 Repeatability
46、 standard deviation, sr2919223539 Repeatability coefficient of variation8,6 %4,6 %4,8 %7,8 %4,0 % Repeatability, 2,83 sr835262100111 Reproducibility standard deviation, sR10883125109289 Reproducibility coefficient of variation32 %a21 %28 %24 %a30 % Reproducibility, 2,83 SR305235353308817 a A statist
47、ical analysis of the results of the interlaboratory test No. 2, only taking into account the nine laboratories having participated in both the interlaboratory tests No. 1 and No. 2, gave a reproducibility coefficient of variation of 18 % for the soya residue and 20 % for the colza (rape) residue. Li
48、censed Copy: sheffieldun sheffieldun, na, Sun Nov 19 13:57:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 6 blank Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 19 13:57:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 8892:1995 BSI 10-1999 List of references See national foreword. Licens
49、ed Copy: sheffieldun sheffieldun, na, Sun Nov 19 13:57:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 8892:1995 BS 4325-10: 1995 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions British Standards are updated by amendment or revision. Users of British Standards should make sure that