1、BRITISH STANDARD BS EN 1134:1995 Method for Determination of sodium, potassium, calcium and magnesium contents of fruit and vegetable juices by atomic absorption spectrometry The European Standard EN1134:1994 has the status of a British Standard UDC 663.81/.82:620.1:543.422.41.6:546.33324146BS EN113
2、4:1995 This British Standard, having been prepared under the directionof the Consumer Products and Services Sector Board, was published under theauthority of theStandards Board and comesinto effect on 15January1995 BSI 11-1999 The following BSI references relate to the work on this standard: Committ
3、ee reference AW/21 Draft for comment89/54811 DC ISBN 0 580 23159 3 Cooperating organizations The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries: Austria Oesterreichis
4、ches Normungsinstitut Belgium Institut belge de normalisation Denmark Dansk Standard Finland Suomen Standardisoimisliito, r.y. France Association franaise de normalisation Germany Deutsches Institut fr Normung e.V. Greece Hellenic Organization for Standardization Iceland Technological Institute of I
5、celand Ireland National Standards Authority of Ireland Italy Ente Nazionale Italiano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portugus da Qualidade Spain Asociacin Espaola de N
6、ormalizacin y Certificacin Sweden Standardiseringskommissionen i Sverige Switzerland Association suisse de normalisation United Kingdom British Standards Institution Amendments issued since publication Amd. No. Date CommentsBS EN1134:1995 BSI 11-1999 i Contents Page Cooperating organizations Inside
7、front cover National foreword ii Foreword 2 1 Scope 3 2 Normative references 3 3 Symbols 3 4 Principle 3 5 Reagents 3 6 Apparatus 3 7 Procedure 4 8 Calculation 5 9 Precision 5 10 Test report 5 Annex A (informative) Bibliography 6 Annex B (informative) Statistical results of the interlaboratory test
8、6 National annex NA (informative) Committees responsible Inside back cover National annex NB (informative) Cross-references Inside back cover Table B.1 6 Table B.2 7 Table B.3 7 Table B.4 8BS EN1134:1995 ii BSI 11-1999 National foreword This British Standard has been prepared under the direction of
9、the Consumer Products and Services Sector Board and is the English language version of EN1134 Fruit and vegetable juicesDetermination of sodium, potassium, calcium and magnesium content by atomic absorption spectrometry (AAS) published by the European Committee for Standardization (CEN). EN1134 was
10、produced as a result of international discussions in which the United Kingdom took an active part. 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 d
11、oes not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, theEN title page, pages2 to8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments
12、incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 1134 October 1994 UDC 663.81/.82:620.1:543.422.41.6:546.33324146 Descriptors: Food products, beverages, fruit and vegetable juices, chemical analysis, determinat
13、ion of content, sodium, potassium, calcium, magnesium, atomic absorption spectrophotometry, flame photometry English version Fruit and vegetable juicesDetermination of sodium, potassium, calcium and magnesium content by atomic absorption spectrometry (AAS) Jus de fruits et de lgumesDosage du sodium,
14、 du potassium, du calcium et du magnsium par spectromtrie dabsorption atomique (SAA) Frucht- und GemsesfteBestimmung der Gehalte an Natrium, Kalium, Calcium und Magnesium Atomabsorptionsspektrometrisches Verfahren (AAS) This European Standard was approved by CEN on1994-09-29. CEN members are bound t
15、o comply with the CEN/CENELEC Internal Regulations 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 Centr
16、al 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 translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as t
17、he official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and UnitedKingdom. CEN European Committee for Standardization Comit Europ
18、en de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1994 Copyright reserved to CEN members Ref No. EN 1134:1994 EEN1134:1994 BSI 11-1999 2 Foreword This European Standard has been prepared by the Technical Committee CEN/TC174, Fruit and vegetab
19、le juicesMethods 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 by endorsement, at the latest by April1995, and conflicting national standards shall be withdrawn at the lat
20、est by April1995. Annexes designated “informative” are given only for information. In this standard Annex A and Annex B are informative. In accordance with the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard. Austria, Belgium, Denmark, Finland,
21、 France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and UnitedKingdom.EN1134:1994 BSI 11-1999 3 1 Scope This European Standard specifies a method for the determination of sodium, potassium, calcium and magnesium content of fruit an
22、d vegetable juices and related products by atomic absorption spectrometry. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are
23、 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 amendment or revision. For undated references the latest edition of the publication referred to applies. ISO5725:1986, Precision
24、 of test methods Determination of repeatability and reproducibility for a standard test method by inter-laboratory tests. ISO3696:1987, Water for analytical laboratory useSpecification and test methods. 3 Symbols For the purposes of this standard, the following symbols apply: c Substance concentrati
25、on Mass concentration 4 Principle Sodium, potassium, calcium and magnesium content is determined by atomic absorption spectrometry (AAS) on the diluted test sample. In samples containing a high proportion of pulp, the calcium content is determined after ashing. In order to prevent a partial ionizati
26、on of the metals in the flame, caesium chloride is added when determining sodium and potassium, and lanthanum, as matrix modifier, when determining calcium and magnesium. 5 Reagents 5.1 General Use only reagents of recognized analytical grade and only water in accordance with at least grade2 of ISO3
27、696:1987. Standard and calibration solutions shall be kept in polyethylene bottles. 5.2 Sodium standard solution, (Na + )=1g/l. Acommercially available sodium standard solution is used. This solution may also be prepared by dissolving2,542g of dried sodium chloride (NaCl) in water and making up to1l
28、itre in a volumetric flask. 5.3 Potassium standard solution, (K + )=1g/l. Acommercially available potassium standard solution is used. This solution may also be prepared by dissolving4,813g of potassium hydrogen tartrate (C 4 H 5 KO 6 ) in water and making up to1litre in a volumetric flask. 5.4 Calc
29、ium standard solution, (Ca + )=1g/l. Acommercially available calcium standard solution is used. This solution may also be prepared by dissolving2,5g of calcium carbonate (CaCO 3 ) in a sufficient quantity of hydrochloric acid(5.8) and making up to1litre with water in a volumetric flask. 5.5 Magnesiu
30、m standard solution, (Mg + )=1g/l. Acommercially available magnesium standard solution is used. This solution may also be prepared by dissolving8,3646g of magnesium chloride (MgCl 2 .6H 2 O) in a sufficient quantity of hydrochloric acid(5.8) and making up to1litre in a volumetric flask. 5.6 Caesium
31、chloride stock solution, (CsCl)=40g/l. Dissolve40g of caesium chloride, CsCl in water and make up to1litre in a volumetric flask. 5.7 Lanthanum stock solution, (La 3+ )=50g/l. Moisten58,6g of lanthanum oxide, La 2 O 3with water in a400ml beaker and carefully add100ml hydrochloric acid (HCl)=370g/l u
32、ntil all of the La 2 O 3is dissolved. Transfer to a1litre volumetric flask and make up to the mark with water. Lanthanum chloride may also be used to prepare this solution. In this case, dissolve134g of LaCl 3 .7H 2 O in water and make up to1litre in a volumetric flask. 5.8 Hydrochloric acid solutio
33、n, (HCl)=100g/l. 6 Apparatus Usual laboratory apparatus and, in particular, the following: 6.1 Atomic absorption spectrometer with burner head for air/acetylene. 6.2 Hollow cathode lamp for sodium 6.3 Hollow cathode lamp for potassium 6.4 Hollow cathode lamp for calcium 6.5 Hollow cathode lamp for m
34、agnesium 6.6 Enzyme test pipettes graduated along the stem only, with long ungraduated delivery tip. 6.7 Pipettes with accuracy equivalent to6.6 (alternative to6.6) e.g.positive displacement capillary pipettes.EN1134:1994 4 BSI 11-1999 7 Procedure 7.1 Preparation of the test sample Normally products
35、 shall not be pretreated and their analysis by this method shall be on a volumetric basis, results being expressed per litre. The analysis of concentrated products may also be carried out on a volumetric basis, after dilution to a known relative density. In this case, the density shall be indicated.
36、 Based on a weighed sample and taking the dilution factor for analysis into account, the results may also be expressed per kilogram of product. In products with high viscosity and/or very high content of cells (for example pulp), determination on the basis of a weighed test sample is the usual proce
37、dure. Clear and cloudy test samples are used without prior centrifugation. Test samples containing a high proportion of pulp are ashed beforehand for the determination of calcium. The ash is absorbed in2ml of hydrochloric acid, c(HCl)=4mol/l, transferred quantitatively into a50ml graduated flask and
38、 made up to the50ml mark with water. The subsequent dilution of the sample is chosen in such a manner that the expected concentration of Ca +lies within the linear range of the calibration curve. The lanthanum content in the solution to be measured amounts to0,5g/100ml. 7.2 Test procedure 7.2.1 Gene
39、ral Special attention is to be paid to the cleanliness of the apparatus used. All glassware shall be rinsed beforehand with water of Grade2, according to ISO3696:1987. For measuring the standard and sample solutions enzyme-testing pipettes(6.6) or their equivalent(6.7) are to used and also suitable
40、glassware for handling small volumes. When diluting cloudy juices, a sample of at least1ml shall be taken. Calibration of the instrument is to be carried out for each series of measurements. When carrying out the determination, make sure that the atomic absorption spectrophotometer is carefully adju
41、sted to the optimum wavelength and perform the measurements according to the instrument manufacturers instructions. If separate stages of the determination are carried out in different laboratories (e.g.general laboratory and instrument room) it is essential that the same batch of water be used for
42、preparing both the sample solutions and the reference solutions. 7.2.2 Sodium determination (wavelength589,0nm) 7.2.2.1 Preparation of the solution for the zero setting Prepare a solution of caesium chloride, (CsCl)=0,4g/100ml, from the stock solution(5.6). 7.2.2.2 Preparation of the reference solut
43、ions According to the expected sodium contents of the samples,3 to5 dilutions are prepared from the sodium standard solution for calibration purposes. Add caesium chloride stock solution to the solutions to be measured, such that (CsCl)=0,4g/100ml. 7.2.2.3 Preparation of the sample solution The dilu
44、tion of the sample is chosen in such a manner that the expected sodium content lies within the linear range of the calibration curve. Add caesium chloride stock solution to the solutions to be measured, such that (CsCl)=0,4g/100ml. 7.2.3 Potassium determination (wavelength766,5nm or769,9nm) 7.2.3.1
45、Preparation of the solution for the zero setting Prepare a solution of caesium chloride, (CsCl)=0,4g/100ml, from the stock solution(5.6). 7.2.3.2 Preparation of the reference solutions According to the expected potassium contents of the samples,3 to5 dilutions are prepared from potassium standard so
46、lution for calibration purposes. Add caesium chloride stock solution to the solutions to be measured, such that (CsCl)=0,04g/l. 7.2.3.3 Preparation of the sample solution The dilution of the sample is chosen in such a manner that the expected potassium content lies within the linear range of the cal
47、ibration curve. Add caesium chloride stock solution to the solutions to be measured, such that (CsCl)=0,04g/l. 7.2.4 Calcium determination (wavelength422,7nm) 7.2.4.1 Preparation of the solution for zero setting Prepare a solution of lanthanum, (La 3+ )=0,5g/100ml, from the stock solution(5.7). 7.2.
48、4.2 Preparation of the reference solutions According to the calcium contents of the samples,3 to5 dilutions are prepared from the calcium standard solution for calibration purposes. Add lanthanum stock solution(5.7) to the solutions to be measured, such that (La 3+ )=0,5g/100ml.EN1134:1994 BSI 11-19
49、99 5 7.2.4.3 Preparation of the sample solution The dilution of the sample (if necessary after sample preparation, see7.1) is chosen in such a manner that the expected calcium content lies within the linear range of the calibration curve. Add lanthanum stock solution(5.7) to the solutions to be measured, such that (La 3+ )=0,5g/100ml. 7.2.5 Magnesium determination (wavelength285,2nm) 7.2.5.1 Preparation of the solution for the zero setting Prepare a solution of lanthanum, (La 3+ )=0,5g/100ml, from the st
