BS ISO 18068-2014 Cotton fibres Test method for sugar content Spectrophotometry《棉纤维 糖含量的试验方法 分光光度法》.pdf

1、BSI Standards PublicationBS ISO 18068:2014Cotton fibres Testmethod for sugar content SpectrophotometryBS ISO 18068:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 18068:2014.The UK participation in its preparation was entrusted to TechnicalCommittee TCI/24

2、, Physical testing of textiles.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution

3、2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 79222 9ICS 59.060.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 July 2014.Amendments issued since

4、 publicationDate Text affectedBS ISO 18068:2014 ISO 2014Cotton fibres Test method for sugar content SpectrophotometryFibres de coton Mthode dessai pour la teneur en sucre SpectrophotomtrieINTERNATIONAL STANDARDISO18068First edition2014-08-15Reference numberISO 18068:2014(E)BS ISO 18068:2014ISO 18068

5、:2014(E)ii ISO 2014 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2014All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet o

6、r an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.org

7、Published in SwitzerlandBS ISO 18068:2014ISO 18068:2014(E) ISO 2014 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 15 Apparatus . 16 Reagents 27 Sampling 38 Procedure. 38.1 Blank test . 38.2 Calibration curve pre

8、paration . 38.3 Determination of sugar content for test specimens 49 Calculation and expression of the results 410 Test report .4BS ISO 18068:2014ISO 18068:2014(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodie

9、s). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and n

10、on-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are descr

11、ibed in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to

12、 the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the I

13、SO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as

14、 well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information.The committee responsible for this document is ISO/TC 38, Textiles, Subcommittee SC 23, Fibres and yarns.iv ISO 2014 All rights reserve

15、dBS ISO 18068:2014ISO 18068:2014(E)IntroductionCotton fibre with normal sugar content might not affect the spinning process. If the sugar content is too high, it might cause storage mildew and metamorphism. During the spinning process, it might also cause twining and breakage, and lower yarn quality

16、 and production efficiency. Spectrophotometry is used as a quantitative determination method to detect the total sugar content, and 3,5-dihydroxytoluene-sulfuric acid solution is used as the colour developer. This International Standard supplies the basic information for sugar content of cotton fibr

17、es. ISO 2014 All rights reserved vBS ISO 18068:2014BS ISO 18068:2014Cotton fibres Test method for sugar content SpectrophotometryWARNING The use of this International Standard might involve the use of hazardous materials, operations, and equipment. This International Standard does not purport to add

18、ress all the safety risks associated with its use. It is the responsibility of the user of this International Standard to establish appropriate safety and health practices and determine the applicability of local regulatory limitations prior to use.1 ScopeThis International Standard specifies a test

19、 method to determine the total sugar content in cotton fibres. Spectrophotometry is used as a quantitative determination method, and 3,5-dihydroxytoluene-sulfuric acid solution is used as a colour developer. This International Standard is applicable to cotton fibres.2 Normative referencesThe followi

20、ng documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 139:2005, Texti

21、les Standard atmospheres for conditioning and testingISO 1130:1975, Textile fibres Some methods of sampling for testingISO 3696:1987, Water for analytical laboratory use Specification and test methodsISO 4793:1980, Laboratory sintered (fritted) filters Porosity grading, classification and designatio

22、n3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1percentage of sugarspercentage content of total sugars contained in cotton fibres (including reducing sugar and non-reducing sugar) in the total mass of cotton fibres under the standard atmosphere

23、4 PrincipleUnder the action of the non-ionic surfactant (fatty acid alkanolamide), sugars in cotton fibres are dissolved in an aqueous solution, then degraded into furfural derivatives in concentrated acid medium (H2SO4). They are later combined with 3,5-dihydroxytoluene to form an orange-yellow com

24、plex. Quantify the content of sugars in the cotton fibres by the spectrophotometric method in comparison with the calibration curve at the wavelength of 425 nm.5 Apparatus5.1 Spectrophotometer, with a wavelength range of 200 nm to 800 nm.5.2 Electronic balance, selected from the following.INTERNATIO

25、NAL STANDARD ISO 18068:2014(E) ISO 2014 All rights reserved 1BS ISO 18068:2014ISO 18068:2014(E)5.2.1 Measuring range 10 g, accurate to 0,001 g.5.2.2 Measuring range 50 g, accurate to 0,1 g.5.3 Water bath, capable of maintaining a constant temperature of (70 2) C.5.4 Conical flask, of capacity 250 ml

26、, with ground stopper or iodine flask.5.5 Pipettes, of capacity 1 ml, 2 ml and 5 ml.An automatic pipette system of the same accuracy as manual pipettes may be used.5.6 Volumetric flasks, of capacity 50 ml and 100 ml.5.7 Graduated cylinders, of capacity 100 ml and 1 000 ml.5.8 Beakers, of capacity 10

27、0 ml and 1 000 ml.5.9 Colorimetric tube, of capacity 25 ml.5.10 Vacuum air pump.5.11 Filter, made from heat resistant glass having a pore size between 40 m and 100 m (pore type P100 in accordance with ISO 4793:1980).5.12 Mechanical shaker, providing rotation or movement sufficient to obtain a ready

28、exchange of liquid between the cotton fibres and the solution used in preparing the extract.The amplitudes of to-and-fro and rotational mechanical shaker should be set as 30 mm70 mm and 20 mm60 mm, respectively. A to-andfro movement at a rate of 60 min1or a rotational frequency of 30 min1has been fo

29、und satisfactory.5.13 Cuvettes, 1 cm.6 Reagents6.1 Distilled water or grade 3 water, complying with ISO 3696:1987.6.2 Sulfuric acid, analytical grade, 1,84 g/ml.6.3 3,5-Dihydroxytoluene, analytical grade.6.4 Fatty acid alkanolamide, technical grade.6.5 D-fructose, analytical grade.6.6 Reagents prepa

30、ration.6.6.1 3,5-Dihydroxytoluene/sulfuric acid solution (0,2 %).Weigh and dissolve 0,2 g of 3,5-dihydroxytoluene with 100 g of H2SO4(approximately 54 ml) in a 100 ml beaker with continuous stirring. This solution should be freshly prepared.2 ISO 2014 All rights reservedBS ISO 18068:2014ISO 18068:20

31、14(E)6.6.2 Fatty acid alkanolamide solution for determination (0,4 g/l).Dissolve 0,4 g of fatty acid alkanolamide in 1 000 ml of water and store it in a beaker. Mix well.6.6.3 Fatty acid alkanolamide solution for extraction (0,05 g/l).Dilute 100 ml of the solution (prepared in 6.6.2) with water to 7

32、00 ml in a beaker. Mix well.7 Sampling7.1 Sample in accordance with ISO 1130:1975. Store the samples to avoid the effect of temperature and humidity.7.2 Randomly select a test specimen, no less than 50 g, from the laboratory samples. Remove any coarse impurities and mix thoroughly.7.3 As specified i

33、n ISO 139:2005, test the test specimen after conditioning it in the standard atmosphere no less than 48 h (or until the difference between successive weighings made at intervals of 2 h does not exceed 0,25 %).7.4 Weigh accurately three portions of the prepared specimen (each portion should weigh 2,0

34、00 g 0,001 g), recorded as m, and reserve the residual sample for further use.8 Procedure8.1 Blank test8.1.1 Pipette 1,0 ml of 0,4 g/l fatty acid alkanolamide solution (6.6.2) into a 25 ml colorimetric tube (5.9).8.1.2 Add 2,0 ml of 3,5-dihydroxytoluene/sulfuric acid solution (6.6.1) immediately to

35、the colorimetric tube preheated to 70 C in a water bath (5.3), and mix them by shaking to form a mixed solution, and again keep the mixed solution at a constant temperature of 70 C for 40 min. Remove the tube from the bath. Subsequently, add further 20 ml of the fatty acid alkanolamide solution (6.6

36、.2) to the mixed solution, mix them by shaking the tube, immediately cool down the resultant solution to room temperature and make it up to the mark with the 0,4 g/l fatty acid alkanolamide solution (6.6.2) and allow it to stand for 5 min to form a final solution. Transfer an appropriate amount of t

37、he final solution into a 1 cm cuvette to form a blank reagent. Measure and record the absorbance of the blank reagent at a wavelength of 425 nm using a Spectrophotometer (5.1).8.2 Calibration curve preparation8.2.1 Standard solutions preparation8.2.1.1 Stock standard solutionPrepare a 2,0 mg/ml stoc

38、k solution of D-fructose by dissolving 0,200 g D-fructose with 100 ml water.8.2.1.2 Standard solutionDilute 0,5 ml, 1,0 ml, 1,5 ml, 2,0 ml, 2,5 ml, 3,0 ml, 4,0 ml, and 5,0 ml of the stock standard solution (see 8.2.1.1), with water in 50 ml volumetric flasks. These solutions contain 0,02 mg/ml, 0,04

39、 mg/ml, 0,06 mg/ml, 0,08 mg/ml, 0,10 mg/ml, 0,12 mg/ml, 0,16 mg/ml, and 0,20 mg/ml of D-fructose, respectively. ISO 2014 All rights reserved 3BS ISO 18068:2014ISO 18068:2014(E)8.2.2 Testing of standard solutionPipette 1,0 ml of each of the standard solutions into a different 25 ml colorimetric tube,

40、 and treat each aliquot in the different tube in the same way as that described in 8.1.2.8.2.3 Calibration curvePrepare a calibration curve with the concentration of the sugar standard solution as the abscissa and the corresponding absorbance (obtained by subtracting the absorbance of the blank reag

41、ent from the absorbance of the sugar standard solution) as the vertical coordinate.Since the sensitivity of fatty acid alkanolamide solution may change slightly over a long period of time, it is good practice to run a calibration curve weekly for correcting slight changes in the standard curve.8.3 D

42、etermination of sugar content for test specimens8.3.1 Place the three test specimens (see 7.4) in three separate 250 ml flasks. Add 200 ml of the 0,05 g/l fatty acid alkanolamide solution (6.6.3) to each flask. Shake for 10 min in the mechanical shaker (5.12). Turn over the cotton fibre with a glass

43、 rod. Shake the flasks for another 10 min and then filter the three test specimen solutions respectively through the filter (5.11) using vacuum air pump (5.10).8.3.2 Pipette 1,0 ml of each of the three test specimen solutions (see 8.3.1) into a separate 25 ml colorimetric tube. Treat in the same way

44、 as 8.1.2.9 Calculation and expression of the results9.1 For each test specimen, correct the absorbance of the test specimen by subtracting the absorbance of the blank reagent from the absorbance of the test specimen. Determine the concentration of the sample solution from the calibration curve. Cal

45、culate the percentage of sugars according to the following formula.xcm=2001000100wherex is the percentage of sugars, in %;c is the concentration of the sugar solution (mg/ml) as read from the calibration curve;m is the mass of the test specimen in grams.9.2 Calculate the mean of the measured values,

46、 rounding to two decimal places.10 Test reportThe test report shall include the following information:a) a reference to this International Standard, i.e. ISO 18068;b) date of receipt and date of analysis;c) description of the sample tested;d) mass of the test specimens;4 ISO 2014 All rights reserved

47、BS ISO 18068:2014ISO 18068:2014(E)e) range of the calibration graph;f) percentage of sugars from the sample;g) any deviation, by agreement or otherwise, from the procedure specified. ISO 2014 All rights reserved 5BS ISO 18068:2014ISO 18068:2014(E) ISO 2014 All rights reservedICS 59.060.10Price based

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