EN 12014-3:2005

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Lebensmittel - Bestimmung des Nitrat- und/oder Nitritgehaltes - Teil 3: Spektralphotometrische Bestimmung des Nitrat- und Nitritgehaltes in Fleischerzeugnissen nach enzymatischer Reduktion von Nitrat zu NitritProduits alimentaires - Détermination de la teneur en nitrates et/ou en nitrites - Partie 3 : Détermination spectrométrique de la teneur en nitrates et en nitrites des produits carnés apres réduction enzymatique des nitrates en nitritesFoodstuffs - Determination of nitrate and/or nitrite content - Part 3: Spectrometric determination of nitrate and nitrite content of meat products after enzymatic reduction of nitrate to nitrite67.120.10Meso in mesni proizvodiMeat and meat products67.050Splošne preskusne in analizne metode za živilske proizvodeGeneral methods of tests and analysis for food productsICS:Ta slovenski standard je istoveten z:EN 12014-3:2005SIST EN 12014-3:2005en01-september-2005SIST EN 12014-3:2005SLOVENSKI
STANDARDSIST ENV 12014-3:19991DGRPHãþD

EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 12014-3
May 2005 ICS 67.120.10 Supersedes ENV 12014-3:1998 English version
Foodstuffs - Determination of nitrate and/or nitrite content - Part 3: Spectrometric determination of nitrate and nitrite content of meat products after enzymatic reduction of nitrate to nitrite
Produits alimentaires - Détermination de la teneur en nitrates et/ou en nitrites des produits carnés - Partie 3: Détermination spectrométrique de la teneur en nitrates et en nitrites après réduction enzymatique des nitrates en nitrites
Lebensmittel - Bestimmung des Nitrat- und/oder Nitritgehaltes -Teil 3: Spektralphotometrische Bestimmung des Nitrat- und Nitritgehaltes in Fleischerzeugnissen nach enzymatischer Reduktion von Nitrat zu Nitrit This European Standard was approved by CEN on 1 April 2005.
CEN members are bound to 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 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 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.
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Precision data.12 Bibliography.14
The nitrate content is calculated from the difference between the spectrometric measurements. 4 Reagents 4.1 General During the analysis, unless otherwise stated, use only reagents and materials of recognized analytical grade and water of at least grade 3 according to EN ISO 3696. When preparing solutions, the purities of the reagents available shall be taken into account. 4.2 Sodium hydroxide solution c(NaOH) ≈ 1 mol/l1)
4.3 Carrez solution No. 1 Dissolve 150 g of potassium hexacyanoferrate(II), K4[Fe(CN)6] ⋅ 3 H2O in water and dilute to 1 000 ml. Store the solution in a brown bottle and replace it every two months. 4.4 Carrez solution No. 2 Dissolve 230 g of zinc acetate, Zn (CH3COO)2 ⋅ 2 H2O, in water and dilute to 1 000 ml.
1) c is the substance concentration SIST EN 12014-3:2005

Dissolve 125 mg of reduced ß-nicotinamide adenine dinucleotide phosphate and 2,5 mg of disodium salt of flavin adenin dinucleotide (mass fraction of at least 88 %) in 50 ml of the imidazole buffer solution (4.5.1). Prepare this solution immediately before use. 4.5.3 Nitrate reductase buffer solution
Dissolve 11 mg of nitrate reductase lyophilisate from aspergillus sp. (EC 1.6.6.2, approximately 0,4 U/mg3)) in 10 ml of imidazole buffer solution (4.5.1) and add 50 mg of ethylenedintrilotetraacetic acid disodium salt-dihydrate.
The solution will be stable for about 14 days if stored at 4 °C. 4.6 Colour reagents 4.6.1 Colour reagent No. 1 Dissolve 8 g of sulfanilamide in 500 ml of water while heating on a water bath (5.3). Cool the solution to room temperature and filter if necessary. Add 330 ml of hydrochloric acid (4.9) while stirring continuously and dilute the solution to 1 000 ml with water. The solution will be stable for several weeks at room temperature. 4.6.2 Colour reagent No. 2 Dissolve 0,330 g of N-(1-naphthyl)ethylenediamine dihydrochloride in 250 ml of water. Keep the solution in a brown bottle and replace it every week. 4.6.3 Colour reagent mixture Prepare the required amount of colour reagent mixture by mixing equal parts by volume of colour reagents No. 1 (4.6.1) and No. 2 (4.6.2) on the day of use. 4.7 Sodium nitrite solutions 4.7.1 General It is recommended to prepare sodium nitrite standard solutions of sodium nitrite on the day of use.
2) The ‘Nitrat’ test kit for the enzymatic determination of nitrate and nitrite is the trade name of a product produced by Boehringer Mannheim/Roche Diagnostics, Mannheim, supplied by r-biopharm, Darmstadt (Germany) This information is given for the convenience of users of this European Standard and does not constitute an endorsement by CEN of the product named. Equivalent products may be used if they can be shown to lead to the same results. 3) U, this unit (often called the International unit or standard unit) is defined as the amount of enzyme which catalyses the transformation of 1 µmol substrate per minute under standard conditions. SIST EN 12014-3:2005

4)
is the mass concentration 5) w is the mass fraction SIST EN 12014-3:2005

5.3 Water bath, capable of being maintained at 100 °C 5.4 Fluted filter papers, nitrate and nitrite free 5.5 pH meter, with pH measuring cell (glass and reference electrodes) 5.6 Spectrometer, for carrying out measurements at a wavelength of 540 nm, with suitable cells, made of glass or plastics which have no significant optical absorption at a wavelength of 540 nm. 6 Procedure 6.1 Preparation of the sample solution Homogenize the laboratory sample with the appropriate equipment (5.2) Take care t
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