1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 1376 : 1997 The Eur
2、opean Standard EN 1376 : 1996 has the status of a British Standard ICS 67.180.10 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Foodstuffs Determination of saccharin in table top sweetener preparations Spectrometric methodBS EN 1376 : 1997 This British Standard, having been p
3、repared 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 April 1997 BSI 1997 The following BSI references relate to the work on this standard: Committee reference AW/-/3 Draft for comment 94/5
4、01924 DC ISBN 0 580 27120 X Amendments issued since publication Amd. No. Date Text affected Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee AW/-/3, Food analysis Horizontal methods, upon which the following bodies were re
5、presented: Association of Public Analysts Department of Trade and Industry (Laboratory of the Government Chemist) Food and Drink Federation Institute of Food Science and Technology Ministry of Agriculture Fisheries and Food Royal Society of ChemistryBS EN 1376 : 1997 BSI 1997 i Contents Page Committ
6、ees responsible Inside front cover National foreword ii Foreword 2 Text of EN 1376 3ii BSI 1997 BS EN 1376 : 1997 National foreword This British Standard has been prepared by Technical Committee AW/-/3 and is the English language version of EN 1376 : 1996 Foodstuffs Determination of saccharin in tab
7、le top sweetener preparations Spectrometric method, published by the European Committee for Standardization (CEN). EN 1377 was produced as a result of international discussions in which the United Kingdom took an active part. Cross-references Publication referred to Corresponding British Standard IS
8、O 3696 : 1987 BS EN ISO 3696 : 1995 Water for analytical laboratory use. Specification and test methods ISO 5725 : 1986, to which informative reference is made in the text, has been superseded by ISO 5725-1 : 1994, ISO 5725-2 : 1994, ISO 5725-3 : 1994, ISO 5725-4 : 1994 and ISO 5725-6 : 1994 which a
9、re identical with BS ISO 5725 Accuracy (trueness and precision) of measurement methods and results, BS ISO 5725-1 : 1994 General principles and definitions, BS ISO 5725-2 : 1994 Basic method for the determination of repeatability and reproducability of a standard measurement method, BS ISO 5725-3 :
10、1994 Intermediate measures of the precision of a standard measurement method, BS ISO 5725-4 : 1994 Basic method for the determination of the trueness of a standard measurement method, and BS ISO 5725-6 : 1994 Use in practice of accuracy values. Compliance with a British Standard does not of itself c
11、onfer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 8, an inside back cover and a back cover.CEN European Committee for Standardization Comite Europe en de Normalisation Europa isches Komi
12、tee fu r Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1996 Copyright reserved to CEN members Ref. No. EN 1376 : 1996 E EUROPEAN STANDARD EN 1376 NORME EUROPE ENNE EUROPA ISCHE NORM September 1996 ICS 67.180.10 Descriptors: Food products, intense sweeteners, chemical analysis, det
13、ermination of content, spectrometric analysis English version Foodstuffs Determination of saccharin in table top sweetener preparations Spectrometric method Produits alimentaires Dosage de la saccharine dans les e dulcorants de table Me thode spectrome trique Lebensmittel Bestimmung von Saccharin in
14、 Tafelsu en Spektralphotometrisches Verfahren This European Standard was approved by CEN on 1996-06-09. 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.
15、 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
16、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 national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Neth
17、erlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.Page 2 EN 1376 : 1996 BSI 1997 Foreword This European Standard has been prepared by the Technical Committee CEN/TC 275, Food analysis Horizontal methods, the Secretariat of which is held by DIN. This European Standard shall be
18、given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by March 1997, and conflicting national standards shall be withdrawn at the latest by March 1997. According to the CEN/CENELEC Internal Regulations, the national standards organizatio
19、ns of 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 and the United Kingdom. Contents Page Foreword 2 1 Scope 3 2 Normat
20、ive references 3 3 Principle 3 4 Reagents 3 5 Apparatus and equipment 3 6 Procedure 4 7 Expression of results 4 8 Precision 5 9 Test report 5 Annexes A (informative) Examples for absorption spectra of a sodium saccharin standard solution 6 B (informative) Precision data 8 C (informative) Bibliograph
21、y 8Page 3 EN 1376 : 1996 BSI 1997 1) c is the substance concentration. 2) r is the mass concentration. 1 Scope This European Standard specifies a spectrometric method for the determination of sodium saccharin and saccharin content in solid table top sweetener preparations prepared from cyclamate/sac
22、charin or saccharin. An inter-laboratory test has been carried out on sweetener tablets 1. 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
23、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. EN ISO
24、3696 Water for analytical laboratory use Specification and test methods 3 Principle Preparation of the sample test solution by dissolving table top sweetener preparation in sodium hydroxide solution. Photometric determination of the sodium saccharin content at the absorption maximum of about 265 nm.
25、 4 Reagents During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and water of at least grade 3 as defined in EN ISO 3696. 4.1 Sodium saccharin, standard substance, with a known content of at least 98 % in dry matter (105 2) C, to constant mass). The loss in
26、mass on drying shall not exceed 15 % (see 6.2). NOTE. For further information on identification and purity, see 2. 4.2 Sodium hydroxide solution, c (NaOH) = 0,1 mol/l. 1) 4.3 Sodium saccharin, stock solution, r (NaC 7 H 4 NO 3 S) 1 g/l. 2) Finely grind an amount of at least 1,5 g of the sodium sacch
27、arin standard substance (see 4.1), then, without delay, dissolve about 280 mg (m 1 ) of the undried ground sodium saccharin standard substance (equivalent to about 250 mg of anhydrous sodium saccharin or 223 mg of saccharin as free imide. For conversion factors (see 7.2) weighed to the nearest 0,1 m
28、g in sodium hydroxide solution (see 4.2) in a 250 ml volumetric flask and dilute to the mark with sodium hydroxide solution (see 4.2). Reserve the remaining finely ground sodium saccharin standard substance for the determination of loss in mass on drying (see 6.2). The determination of loss in mass
29、on drying is carried out immediately. Calculate the mass concentration, r, of anhydrous sodium saccharin, in milligrams per litre of the stock solution, using the following equation: (1) r = m 1 3 (1002 L D )3 4 100 where: m 1 is the mass of undried sodium saccharin standard substance used for the s
30、tock solution, in milligrams L D is the loss in mass on drying, in % 4.4 Sodium saccharin standard solutions Pipette 2,0 ml, 5,0 ml, 10,0 ml and 15,0 ml portions of the sodium saccharin stock solution (see 4.3) into separate 100 ml volumetric flasks and dilute to the mark with sodium hydroxide solut
31、ion (see 4.2). 1 l of these solutions contains about 20 mg, 50 mg, 100 mg and 150 mg, respectively, of anhydrous sodium saccharin. NOTE. Additional solutions with concentrations within the linear range may be prepared for the calibration graph. 5 Apparatus and equipment Usual laboratory apparatus an
32、d, in particular, the following. 5.1 Spectrometer, suitable for measurements in the ultraviolet (UV) range. 5.2 Quartz cuvettes, with an optical path length of 1 cm.Page 4 EN 1376 : 1996 BSI 1997 6 Procedure 6.1 Determination of average tablet mass Determine the mass of at least 20 sweetener tablets
33、 to the nearest 0,1 mg and calculate the average mass (m 2 ) of one tablet. NOTE. For improved accuracy the use of 100 tablets is recommended. 6.2 Determination of loss in mass on drying of standard substance Weigh about 1,0 g to the nearest 0,1 mg, of the reserved finely ground sodium saccharin sta
34、ndard substance used for the preparation of the stock solution (see 4.3), dry this portion to constant mass at 105 C 2C and determine the loss in mass on drying in percent (L D ) by weighing. 6.3 Preparation of the sample test solution Dissolve an amount (m 0 ) of finely ground table top sweetener p
35、reparation equivalent to about 35 mg of sodium saccharin weighed to the nearest 0,1 mg in the sodium hydroxide solution (see 4.2)i na5 0m l volumetric flask and dilute to the mark. Pipette 20,0 ml of this solution into a 100 ml volumetric flask and dilute to the mark with sodium hydroxide solution (
36、see 4.2). 6.4 Determination 6.4.1 Measure the absorption spectrum of the standard sodium saccharin solution (see 4.4) containing about 100 mg of anhydrous sodium saccharin in 1000 ml between wavelengths of 230 nm and 300 nm in quartz cuvettes (see 5.2) with sodium hydroxide solution (see 4.2) as ref
37、erence and determine the wavelength of the absorption maximum (about 265 nm). 6.4.2 Prepare the calibration graph by measuring the absorptions of the standard sodium saccharin solutions (see 4.4) at the absorption maximum determined in 6.4.1. 6.4.3 Measure the absorption spectrum of the sample test
38、solution as described in 6.4.1 and determine the absorption in the absorption maximum determined in 6.4.1. If the shape of the curve obtained for the sample test solution differs from that of the standard solution, it is probable that an interfering substance is present. In this case, the method is
39、not applicable. Verify the applicability by determining the absorptions 15 nm above and below the wavelength of the absorption maximum (about 265 nm). Absorption ratios between these values and the maximum absorption shall not differ from those obtained when using the sodium saccharin standard solut
40、ions (see 4.4). Examples for absorption spectra of sodium saccharin are given in annex A. 7 Expression of results 7.1 General Plot the absorption values of the sodium saccharin standard solutions (see 4.4) on millimetre graph paper against the sodium saccharin concentrations in milligrams per litre.
41、 The calibration graph should be linear. Read off the sodium saccharin concentration, x,i n milligrams per litre, corresponding to the absorption of the sample test solution from the calibration graph. An alternative calculative evaluation using the regression graph may be used. 7.2 Calculation 7.2.
42、1 Calculate the mass fraction, w 1 , of anhydrous sodium saccharin, in milligrams per kilogram table top sweetener preparation, using the following equation: (2) w 2 = x3 0,253 10 6 m 0 where x is the concentration of anhydrous sodium saccharin in the sample test solution, read off from the calibrat
43、ion graph, in milligrams per litre m 0 is the initial sample mass, in milligrams 7.2.2 Calculate the mass fraction, w 2 , of anhydrous sodium saccharin, in milligrams per tablet, using the following equation: (3) w 2 = x3 m 2 3 0,25 m 0 where: m 2 is the average tablet mass (see 6.1), in milligrams
44、m 0 , x see equation (2) 7.2.3 Calculate the mass fraction, w 3 , of sodium saccharin dihydrate, in milligrams per kilogram table top sweetener preparation, using the following equation: w 2 = w 1 3 1,175 (4) 7.2.4 Calculate the mass fraction, w 4 , of saccharin, in milligrams per kilogram table top
45、 sweetener preparation, using the following equation: w 4 = w 1 3 0,893 (5) 7.2.5 Report the result according to current legislation by one of the values obtained in 7.2.1 to 7.2.4 after rounding to one decimal place.Page 5 EN 1376 : 1996 BSI 1997 8 Precision Details of the inter-laboratory test of
46、the precision of the method according to ISO 5725 : 1986 3 are summarized in annex B. The values derived from the inter-laboratory test may not be applicable to analyte concentration ranges and matrices other than given in annex B. 8.1 Repeatability The absolute difference between two single test re
47、sults found on identical test material by one operator using the same apparatus within the shortest feasible time interval will exceed the repeatability limit r in not more than 5 % of the cases. The value is: r = 0,42 mg/100 g 8.2 Reproducibility The absolute difference between two single test resu
48、lts on identical test material reported by two laboratories will exceed the reproducibility limit R in not more than 5 % of the cases. The value is: R = 0,85 mg/100 g 9 Test report The test report shall contain at least the following data: all information necessary for the identification of the samp
49、le; a reference to this European Standard or to the method used; the results and the units in which the results have been expressed; if the repeatability of the method has been verified; any particular points observed in the course of the test; any operations not specified in the method or regarded as optional which might have affected the results.Page 6 EN 1376 : 1996 BSI 1997 Annex A (informative) Examples for absorption spectra of a sodium saccharin standard solution Sample SodiumSaccharin Solvent NaO
