1、m 3404589 0086942 405 BRITISH STANDARD Method for Determination of sodium, potassium, calcium and magnesium contents of fruit and vegetable juices by atomic absorption spectrometry “he European Standard EN 1134 : 1994 has the status of a British Standard UDC 663 811 82 620 1 543 422 41 6 546 3332414
2、6 BS EN 1134 : 1995 BS EN 1134 : 1995 Products and Services Sector Board, was published under the authority of the Standards Board and comes into effect on 15 January 1995 Amd. No. Cooperating organizations Date lext affected The European Committee for Standardization (CEN), under whose supervision
3、this European Standard was prepared, comprises the national standards organizations of the following countries: Austria Belgium Denmark Finland France Germany Greece Iceland Ireland Italy Luxembourg Netherlands Norway Portugal Spain Sweden Switzerland United Kingdom Oesterreichisches Normungsinstitu
4、t Institut belge de normalisation Dansk Standard Suomen Standardisoimisliito, r. y. Association franaise de normalisation Deutsches Institut fr Normung e.V. Hellenic Organization for Standardization kchnological Institute of Iceland National Standards Authority of Ireland Ente Nazionale Italiano di
5、Unificazione Inspection du Travail et des Mines Nederlands Normalisatie-institut Norges Standardiseringsforlbund Instituto Portugus da Qualidade Asociacin Espaola de Normalizacin y Certificacin Standardiseringskommissionen i Sverige Association suisse de normalisation British Standards Institution 0
6、 BSI 1995 The following BSI references relate to the work on this standard: Committee reference AW/21 Draft for comment 89/54811 DC ISBN O 580 23159 3 = 3404589 0086944 288 BS EN 1134 : 1995 Contents Cooperating organizations National foreword w?e Inside front cover 1 Fore word Method 1 Scope 2 Norm
7、ative references 3 Symbols 4 Principle 5 Reagents 6 Apparatus 7 Procedure 8 Calculation 2 9 Precision 5 10 lst report 5 Annexes A (informative) Bibliography 6 National annexes NA (informative) Committees responsible NB (informative) Cross-references B (informative) Statistical results of the interla
8、boratory test 7 Inside back cover Inside back cover National foreword This British Standard has been prepared under the direction of the Consumer Products and Services Sector Board and is the English language version of EN 1134 Fruit and vegetable juices - Determination of sodium, potassium, calcium
9、 and mqmsium corent by atomic absorption spectrometry (AAS) published by the European Committee for Standardization (CEN). EN 1134 was produced as a result of international discussions in which the United Kingdom took an active part. Compliance with a British Standard does not of itself confer immun
10、ity from legal obligations. i 3404589 0086945 114 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 1134 October 1994 UDC 663.811.82: 620.1 : 543.422.41.6:546.33324146 Descriptors: Food products, beverages, fruit and vegetable juices, chemical analysis, determination of content, sodium, potassium
11、, calcium, magnesium, atomic absorption spectrophotometry, flame photometry English version Fruit and vegetable juices - Determination of sodium, potassium, calcium and magnesium content by atomic absorption spectrometry (AAS) Jus de fruits et de lgumes - Dosage du sodium, du potassium, du calcium e
12、t du magnsium par spectromtrie dabsorption atomique (SAA) Atomabsorptionsspektrometrisches Verfahren Frucht- und Gemsesfte - Bestimmung der Gehalte an Natrium, Kalium, Calcium und Magnesium - (AAS) This European Standard was approved by CEN on 1994-09-29. CEN members are bound to comply with the CEN
13、KENELEC 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 Central Secretariat or to a
14、ny 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 the official versions.
15、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 United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation E
16、uropisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels O 1994 Copyright reserved to CEN members Ref No. EN 1134 : 1994 E m 3404589 008b94b 050 m Page 2 EN 1134 : 1994 Foreword This European Standard has been prepared by the lchnical Committee CEN/TC 174, Fruit and veg
17、etable 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 by endorsement, at the latest by April 1995, and conflicting national standards shall be withdrawn at
18、 the latest by April 1995. Annexes designated informative are given only for information. In this standard annexes A and B are informative. In accordance with the CENKENELEC Internal Regulations, the following countries are bound to implement this European Standard. Austria, Belgium, Denmark, Finlan
19、d, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. W 3404589 0086947 T97 W Page 3 EN 1134 : 1994 1 Scope This European Standard specifies a method for the determination of sodium, potassium, calcium and magne
20、sium content of fruit and 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
21、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 amendment or revision. For undated references the latest edition of the publication referred to applies.
22、 IS0 5725 : 1986 IS0 3696 : 1987 Precision of test methods - Determination of repeatability and rqwoducibility for a standard test method by inter-laboratory tests Water for analytical laboratory use - Specification and test methods 3 Symbols For the purposes of this standard, the following symbols
23、apply: c Substance concentration p 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 ord
24、er to prevent a partial ionization 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 accorda
25、nce with at least grade 2 of IS0 3696 : 1987. Standard and calibration solutions shall be kept in polyethylene bo ttles . 5.2 Sodium standard solution, p(Na+) = 1 gil. A commercially available sodium standard solution is used. This solution may also be prepared by dissolving 2,542 g of dried sodium
26、chloride (NaC1) in water and making up to 1 litre in a volumetric flask. 5.3 Potassium standard solution, p(K+) = 1 gil. A commercially available potassium standard solution is used. This solution may also be prepared by dissolving 4,813 g of potassium hydrogen tartrate (C4H5K06) in water and making
27、 up to 1 litre in a volumetric flask. 5.4 Calcium standard solution, p(Ca+ +) = 1 gil. A commercially available calcium standard solution is used. This solution may also be prepared by dissolving 2,5 g of calcium carbonate (CaC03) in a sufficient quantity of hydrochloric acid (5.8) and making up to
28、1 litre with water in a volumetric flask. 5.5 Magnesium standard solution, p (Mg + + ) = 1 gl. A commercially available magnesium standard solution is used. This solution may also be prepared by dissolving 8,3646 g of magnesium chloride (MgC12.6H20) in a sufficient quantity of hydrochloric acid (5.8
29、) and making up to 1 litre in a volumetric flask. 5.6 Caesium chloride stock solution, p(CsC1) = 40 gl. Dissolve 40 g of caesium chloride, CsC1 in water and make up to 1 litre in a volumetric flask. 5.7 Lanthanum stock solution, p(La3+) = 50 gl. Moisten 58,6 g of lanthanum oxide, La203 with water in
30、 a 400 ml beaker and carefully add 100 ml hydrochloric acid p(HC1) = 370 gil until all of the La203 is dissolved. Transfer to a 1 litre volumetric flask and make up to the mark with water. Lanthanum chloride may also be used to prepare this solution. In this case, dissolve 134 g of LaC13.7H20 in wat
31、er and make up to 1 litre in a volumetric flask. 5.8 Hydrochloric acid solution, p(HC1) = 100 gil. 6 Apparatus Usual laboratory apparatus and, in particular, the following: 6.1 Atomic absorption spectrometer with burner head for aidacetylene. 6.2 Hollow cathode lamp for sodium. 6.3 Hollow cathode lu
32、mp for potassium. 6.4 Hollow cathode lamp for calcium. 6.5 Hollow cathode lamp for magnesium. 6.6 Enxyme test pipettes graduated along the stem only, with long ungraduated delivery tip. 3404589 008b948 923 Page 4 EN 1134: 1994 6.7 Pipettes with accuracy equivalent to 6.6 (alternative to 6.6) e.g. po
33、sitive displacement capillary pipettes. 7 Procedure 7.1 Preparation of the test sample Normaly products 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 volu
34、metric basis, after dilution to a known relative density. In this case, the density shall be indicated. 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 andior very high cont
35、ent of ceiis (for example pulp), determination on the basis of a weighed test sample is the usual procedure. 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 absorb
36、ed in 2 ml of hydrochloric acid, c(HC1) = 4 moV1, transferred quantitatively into a 50 ml graduated flask and made up to the 50 ml mark with water. The subesequent dilution of the sample is chosen in such a manner that the expected concentration of Ca+ + lies within the linear range of the calibrati
37、on curve. The lanthanum content in the solution to be measured amounts to 0,5 i00 ml. 7.2 Test procedure 7.2.1 General Special attention is to be paid to the cleanliness of the apparatus used. All glassware shall be rinsed beforehand with water of Grade 2, according to IS0 3696 : 1987. For measuring
38、 the standard and sample solutions enzyme-testing pipettes (6.6) or their equivalent (6.7) are to used and also suitable glassware for handling small volumes. When diluting cloudy juices, a sample of at least 1 ml shall be taken. Calibration of the instrument is to be carried out for each series of
39、measurements. When carrying out the determination, make sure that the atomic absorption spectrophotometer is carefully adjusted to the optimum wavelength and perform the measurements according to the instrument manufacturers instructions. If separate stages of the determination are carried out in di
40、fferent laboratories (e.g. general laboratory and instrument room) it is essential that the same batch of water be used for preparing both the sample solutions and the reference solutions. 7.2.2 Sodium determination (wavelength 589, O nm) 7.2.2.1 Preparation of the solution for the zero setting Prep
41、are a solution of caesium chloride, p(CsC1) = 0,4 d100 ml, from the stock solution (5.6). 7.2.2.2 Preparation of the reference solutions According to the expected sodium contents of the samples, 3 to 5 dilutions are prepared from the sodium standard solution for calibration purposes. Add caesium chl
42、oride stock solution to the solutions to be measured, such that p(CsC1) = 0,4 dl00 ml. 7.2.2.3 Preparation of the sample solution The dilution 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 s
43、olution to the soutions to be measured, such that p(CsCl)= 0,4 d100 ml. 7.2.3 Potassium determination (wavelength 766,s nm or 769,9 nm) 7.2.3.1 Preparation of the solution for the zero setting Prepare a solution of caesium chloride, p(CsC1) = 0,4 dl00 ml, from the stock solution (5.6). 7.2.3.2 Prepa
44、ration of the reference solutions According to the expected potassium contents of the samples, 3 to 5 dilutions are prepared from potassium standard solution for calibration purposes. Add caesium chloride stock solution to the solutions to be measured, such that p(CsC1) = 0,04 g/l. 7.2.3.3 Preparati
45、on 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 calibration curve. Add caesium chloride stock solution to the solutions to be measured, such that p(CsC1) = 0,04 g/l. 7.2.4 Calcium determination (w
46、avelength 422,7 nm) 7.2.4.1 Preparation of the solution for m setting Prepare a solution of lanthanum, p(La3+) = 0,5 g/100 ml, from the stock solution (5.7). 7.2.4.2 Preparation of the reference solutions According to the calcium contents of the samples, 3 to 5 dilutions are prepared from the calciu
47、m standard solution for calibration purposes. Add lanthanum stock solution (5.7) to the solutions to be measured, such that p(La3+) = 0,5 d100 ml. W 3404589 0086949 BbT Page 5 EN 1134 : 1994 7.2.4.3 Preparation of the sample solution The dilution of the sample (if necessary after sample preparation,
48、 see 7.1) 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 p(La3+) = 0,5 g100 ml. 7.2.5 Magnesium determination (wavelength 285,2 nm) 7.2.5.1 Preparation o
49、f the solution for the mo setting Prepare a solution of lanthanum, p(La3+) = 0,5 g/lOO ml, from the stock solution (5.7). 7.2.5.2 Preparation of the reference solutions According to the expected magnesium contents of the samples, 3 to 5 dilutions are prepared from the magnesium standard solution for calibration purposes. Add lanthanum stock solution (5.7) to the solutions to be measured, such that p(La3+) = 0,5 g100 ml. 7.2.5.3 Preparation of the sample solution The dilution of the sample is chosen in such a manner that the expected magnesium content li
