1、 STD-BSI BS EN L3L7b-ENGL 2000 aai Lb24bb9 OBbL3b7 291 H BRITISH STANDARD Fruit and vegetable juices - Determination of total sulfur dioxide by distillat ion The European Standard EN 131962000 has the status of a British Standard ICs 67.160.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY
2、 COPYRIGHT LAW 3s EN 13196:2000 STDmBSI BS EN b3LSb-ENGL 2000 Lb2LibbS 08bL3b8 028 BS EN 131962000 been prepared under the direction of the Consumer Products and Services Sector Committee, was published under the authority of the Standards Committee and comes into effect on 16 July 2000 Amd. No. Q B
3、SI 07-2000 ISBN O 580 34341 3 National foreword Date Comments This British Standard is the official English language version of EN 13196:2000. The UK participation in its preparation was entrusted to Technid Committee AW/2l, FNit and vegetable juices, which has the responsibility to: - aid enquirem
4、to undemtand the tee - present to the responsible European committee any enquiries on the interpreation, or proposals for change, and keep the UK interests informed; - monitor related intedonal and European developments and promulgate them in the UK. A iist of organizations represented on this commi
5、ttee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Sandards Catalogue under the section entitled “Intedonal Standards Correspondence Index”, or by using t
6、he “Find” faciiity of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a conkact. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from
7、 iegai obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 11 and a back cover. The BSI copyright notice displayed in this document india when the document was last issued. STD.BS1 BS EN L3LSb-ENGL 2000 111 L624669 OBbL3b Tb4 EURO
8、PEAN STANDARD EN 13196 NORME EUROPENNE EUROPISCHE NORM March 2000 ICs 67.160.20 English version Fruit and vegetable juices - Determination of total sulfur dioxide by distillation Jus de fruits et de lgumes - Dosage du dioxyde de soufre total par distillation Frucht- und Gemsesfte - Bestimmung des Ge
9、samtschwefeldioxids durch Destillation This European Standard was approved by CEN on 20 January 2000. CEN members are bound to comply with the CENICENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. U
10、p-to-date lists and bibliographical references concerning sich national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by traislation un
11、der the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as he official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Lux
12、embourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Central Secretariat: rue de Stassari, 36 8-1050 Brussels O 2000 CEN All rights of exploitation in any form and b
13、y any means reserved worldwide for CEN national Members. Ref. No. EN 131 96:2000 E STD-BSI BS EN L319h-ENGL 2000 m Lb24bh7 OfbL370 786 Page 2 EN 131 96:2000 Contents Foreword . 3 I Scope 3 2 Normative references . 4 3 Symbols - 4 4 Principle . 4 5 Reagents 4 6 Apparatus 5 7 Procedure 5 8 Calculation
14、 . 6 9 Precision 6 10 Test report . 7 Annex A (informative) Bibliography 8 Annex B (informative) Statistical results of the interlaboratory test . 9 Annex C (informative) Examples of typical distillation systems 10 O BSI 07-2000 STD-ES1 ES EN L3LSh-ENGL 2000 W Lh24bb9 OBbL371 hL2 Page 3 EN 131 96:20
15、00 Foreword This European Standard has been prepared by Technical Committee CENTTC 174, Fruit and vegetable juices - Methods of analysis, the Secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or
16、by endorsement, at the latest by September 2000, and conflicting national standards shall be withdrawn at the latest by September 2000. According to the CENICENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Au
17、stria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. O BSI 07-2000 Page 4 EN 131 96:2000 1 Scope This European Standard specifies a distillation method for the
18、 quantitative determination of total sulfur dioxide in fruit or vegetable juices and related products. This method applied to onions, leek or cabbage products can lead to false positive results. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from
19、 other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendmen
20、t or revision. For undated references the latest edition of the publication referred to applies. EN IS0 3696:1995, Water for analytical laboratory use - Specification and fest method (IS0 3696:1987). 3 Symbols For the purposes of this standard the following symbols apply: c Substance concentration;
21、p Mass concentration; 4 Volume fraction. 4 Principle The acidified fruit or vegetable juice to be analysed is heated in a distillation system. The sulfur dioxide liberated is swept out of the system with nitrogen or air and is bubbled through a neutralized solution of hydrogen peroxide where it is o
22、xidized to sulfuric acid. The quantification of the sulfur dioxide is then carried out by titration against a standardized sodium hydroxide solution. 5 Reagents 5.1 General Use only reagents of recognized analytical grade and only water in accordance with at least grade I of EN IS0 3696:1995. 5.2 Ph
23、osphoric acid, 4 (H,PO,) = 85 %. 5.3 Ethanol, 4 (CH,CH,OH) = 50 %. 5.4 Mixed indicator solution Dissolve 100 mg of methyl red and 50 mg of methylene blue in approximately 50 ml of ethanol (see 5.3) with stirring. After the indicators have dissolved make the solution up to 100 ml with ethanol. 5.5 Hy
24、drogen peroxide solution, 4 (H202) = 30 %. O BSI 07-2000 STD.BS1 BS EN L3Lh-ENGL 2000 II Lb24bb9 OBbl1373 495 Page 5 EN 131 96:2000 5.6 Hydrogen peroxide solution, (H202) = 0,9 %. Dilute 3,OO mi of the hydrogen peroxide solution (see 5.5) to 100 mi in water. 5.7 Sodium hydroxide solution, c (NaOH) =
25、 0,OI mol/l. Dilute an appropriate standardized solution of sodium hydroxide solution (0,l mol/l or 1 ,O mol/l) to 0,Ol mol/l in freshly boiled water. This solution should be prepared freshly every week or standardized against a known mass of potassium hydrogen phthalate using phenolphthalein as the
26、 indicator. 5.8 Purified nitrogen gas or air supply 6 Apparatus Usual laboratory apparatus and, in particular, the following: 6.1 Distillation system A distillation system similar to the one shown in Figure C.l is used to carry out this determination. The condenser of this type is a critical feature
27、 of the method. NOTE Sodium hydroxymethylsulfonate can be used to assess the reliability of the apparatus. 6.2 10 ml burette graduated in 0,02 ml units. 7 Procedure 7.1 Preparation of the test sample Normally products shall not be pre-treated and their analysis by this method shall be on a volumetri
28、c basis, results being expressed per litre of sample. The analysis of concentrated samples may also be carried out on a volumetric basis, after dilution to a known relative density. In this case, the relative density shall be indicated. Based on a weighed sample and taking the dilution factor for an
29、alysis into account, the results may also be expressed per kilogram of product. In products with a high viscosity and/or a very high content of cells (for example pulp), determination on the basis of a weighed test sample is the usual procedure. Mix cloudy samples well before dilution. 7.2 Test proc
30、edure If a fruit or vegetable juice or related product preserved with sulfur dioxide ( 50mgll) is analysed, place 20 ml of the test sample in a 100 ml round bottom flask. Connect this flask to the distillation system as shown in Figure C.l in annex C. 5 ml of phosphoric acid (see 5.2) is placed in t
31、he dropping funnel. If a fruit or vegetable juice or related product, unpreserved with sulfur dioxide (e 50 mg/l), is analysed place 50 ml of the test sample in the 250 ml round bottom flask. Connect this flask to the distillation system as shown in Figure C.l in annex C. 15 ml of phosphoric acid (s
32、ee 5.2) is placed in the dropping funnel. 2 or 3 mi of the hydrogen peroxide solution (see 5.6) is added to the absorption receiver, shown as B in Figure C.l in annex C. To this solution is added 2 drops of the mixed indicator solution (see 5.4) and the hydrogen peroxide solution is neutralized with
33、 the sodium hydroxide solution (see 5.7). This flask is then connected to the distillation system. Allow the phosphoric acid (see 5.2) to enter the distillation flask from the dropping funnel. The distillation fiask is then heated to boiling with a small flame (4 cm to 5 cm) positioned directly bene
34、ath the flask. The flask is heated over a suitable disk with a small hole cut in it (30 mm diameter) to stop the product from burning in the flask. A wire gauze should not be used. O BSI 07-2000 STD-BSI BS EN L3LSb-ENGL 2000 Lb24bb9 OBbL374 323 I Page 6 EN 131 96:2000 During the distillation process
35、 air or nitrogen gas passes through the apparatus to “sweep out“ the sulfur dioxide from the distillation flask into the receiver vessel. A flow rate of approximately 40 I per hour shall be used. After the reflux has commenced heating shall be continued for 15 minutes. After the distillation is comp
36、lete the receiver is removed and the receiver tip is washed with water both internally and externally. The wash water is collected in the receiver flask. The sulfuric acid produced, by the oxidation of the sulfur dioxide, is then titrated against the sodium hydroxide solution (see 5.7) added from a
37、burette (see 6.2) to give a green colour end point. 8 Calculation The total level of sulfur dioxide p is given by the following equations and shall be expressed in milligrams per litre without decimals: For 50 ml of test sample: p = a x 6,4 (1 1 For 20 ml of test sample: p=axl6 (2) where: a is the v
38、olume (mi) of sodium hydroxide (see 5.7) used to restore the green colour to the solution in the receiver flask. NOTE 1 ml NaOH (c = 0,Ol mol/l) is equivalent to 0,32 mg SOr. 9 Precision Details of the interlaboratory test on precision of the method are summarized in annex B. The values derived from
39、 the interlaboratory test may not be applicable to analyse concentration ranges and matrices other than given in annex B. 9.1 Repeatability The absolute difference between two single results found on identical test material by one operator using the same apparatus within the shortest feasible time i
40、nterval will exceed the repeatability limit r in not more than 5 % of the cases. The value is: r = 0,8 mgil. 9.2 Reproducibility The absolute difference between single test results on identical test material reported by two laboratories will exceed the reproducibility limit R in not more than 5 % of
41、 the cases. The value is: R = 33 mg/l. O BSI 07-2000 STD.BSI BS EN L3LSb-ENGL 2000 Lb24bbS ObL375 Zb8 Page 7 EN 131 96:ZOOO ?O Testreport The test report shall contain the following data: - all information necessary for the identification of the sample (kind of sample, origin of sample, designation)
42、; - a reference to this European Standard; - the date and type of sampling procedure (if known); - the date of receipt; - the date of test; - test results and units in which they have been expressed; - whether the repeatability has been verified; - any particular points observed in the course of the
43、 test; - any operations not specified in the method or regarded as optional, which might have affected the results. O BSI 07-2000 STDsBSI BS EN 1317b-ENGL 2000 Lb24bb7 OBbL37b LT4 m Page 8 EN 131 96:2000 Annex A (informative) Bibliography Determination of total sulfur dioxide. Method No. 7a (1 987).
44、 - In: The collected Analyses of the International Federation of Fruit Juice Producers. - Loose-leaf edition as of 1991. - Zug: Swiss Fruit Union. International collection of methods for the analysis of wines, method A17. Edited by Office International de la Vigne et du Vin, 1 rue Roquepine, F-75008
45、 Paris. Official Journal of the European Communities (3 October 1990), L272, Volume 33, 15-34. Measurement of sulfur dioxide in wines and grape musts. IS0 57251 986, Precision of test methods - Determination of repeatability and reproducibility for a standard test method by inter-laboratory tests. E
46、N 1988-1 : 1998, Foodstuffs - Determination of suifite - Part 1: Optimized Monier- Williams method. O BSI 07-2000 - STD-BSI BS EN L3LSb-ENGL 2000 L624669 0863377 030 6 2 I 30 Page 9 EN 131 96:2000 Repeatability relative standard deviation (RSD,) (%) Repeatability limit (r) (mgll) Annex B (informativ
47、e) 4,s 1,7 039 0,7 Statistical results of the interlaboratory test In accordance with IS0 5725:1986, the following parameters have been defined in an interlaboratory test. (For literature pertaining to the method see annex A.) The test was conducted by the Max von Pettenkofer Institute of the Federa
48、l Health Office, Food Chemistry Department, Berlin, BRD. Year of interlaboratory test: 1986; Number of laboratories: 8 (9); Number of samples: 2. Table B.1 Sample Vumber of laboratories retained after eliminating outliers Number of outliers (laboratories) Number of accepted results 6 3 30 Mean value
49、 (Y) (mgll) I 72 I 16,1 Repeatability standard deviation (s,) (mgll) 1 0,323 1 0,271 Reproducibility standard deviation (sR) (mg/l) Reproducibility relative standard deviation (RSD,) (%) 1,472 20,4 0,9762 681 Reproducibility limit (R) (mg/l) I 4,l I 2,7 Sample types: - A: grapejuice; - B: apple juice. O BSI 07-2000 STD-BSI BS EN L329b-ENGL 2000 W lb24bb9 OBbL37B T77 9 Page 10 EN 131 96:2000 Annex C (informative) Examples of typical distillation systems Key 1 2 Absorption receiver/bubbler 3 Water pump 100 ml or 250 ml round bottom flask The dimensions are
