BS-4897-3-1983 ISO-779-1982.pdf

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1、BRITISH STANDARD CONFIRMED JULY 1993 BS 4897-3: 1983 ISO 779:1982 Trace metal contents of pulps Part 3: Method for determination of iron content by 1,10-phenanthroline photometric and flame atomic absorption spectrometric methods UDC 676.014.2:543.064:546.72 Licensed Copy: sheffieldun sheffieldun, n

2、a, Fri Dec 01 09:02:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4897-3:1983 This British Standard, having been prepared under the direction of the Paper Standards Committee, was published under the authority of the Board of BSI and comes into effect on 29 July 1983 BSI 12-1999 First published a

3、s BS 4897 May 1973 First (Part) revision as BS 4897-3 July 1983 The following BSI references relate to the work on this standard: Committee reference PAM/11 Draft for comment 81/61951 DC ISBN 0 580 13354 0 Committees responsible for this British Standard The preparation of this British Standard was

4、entrusted by the Paper Standards Committee (PAM/-) to Technical Committee PAM/11 upon which the following bodies were represented: British Fibreboard Packaging Association British Paper and Board Industry Federation (PIF) British Printing Industries Federation British Wood Pulp Association Envelope

5、Makers and Manufacturing Stationers Association Her Majestys Stationery Office Man-made Fibres Producers Committee Ministry of Defence Paper Sack Development Association Ltd. Pira (The Research Association for the Paper and Board, Printing and Packaging Industries) Post Office Society of British Pri

6、nting Ink Manufacturers University of Manchester Institute of Science and Technology Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 09:02:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4897-3:1983 BSI 12-1999i Contents Page Committee

7、s responsibleInside front cover National forewordii 0Introduction1 1Scope and field of application1 2References1 3Method A: 1,10-Phenanthroline photometric method1 4Method B: Flame atomic absorption spectrometric method3 5Test report4 Table 12 Table 23 Publications referred toInside back cover Licen

8、sed Copy: sheffieldun sheffieldun, na, Fri Dec 01 09:02:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4897-3:1983 ii BSI 12-1999 National foreword This Part of this British Standard has been prepared under the direction of the Paper Standards Committee and is identical with ISO 779:1982 “Pulps De

9、termination of iron content 1,10-Phenanthroline photometric and flame atomic absorption spectrometric methods” published by the International Organization for Standardization (ISO). Parts 1, 2, 3 and 4 of this standard supersede BS 4897:1973 which is withdrawn. Part 1 of this standard is identical w

10、ith ISO 777:1982 “Pulps Determination of calcium content edta Titrimetric and flame atomic absorption spectrometric methods”. Part 2 of this standard is identical with ISO 778:1982 “Pulps Determination of copper content Extraction-photometric and flame atomic absorption spectrometric methods”. Part

11、4 of this standard is identical with ISO 1830:1982 “Pulps Determination of manganese content Sodium periodate photometric and flame atomic absorption spectrometric methods”. Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a British

12、 Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards it is current practice to use a full point on the baseline a

13、s a decimal marker. Wherever the words “International Standard” appear, referring to this Part of this standard, they should be read as “this Part of this British Standard”. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are resp

14、onsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references International StandardsCorresponding British Standards ISO 638:1978BS 4502:1980 Method for determination of dry-matter content of pulps (Identical) IS

15、O 1762:1974BS 4896:1973 Method for the determination of ash of pulp (Technically equivalent) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may

16、 have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 09:02:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4897-3:1983 BSI 12-19991 WARNING The methods specified in this International Stand

17、ard involve the use of some hazardous chemicals and of gases that can form explosive mixtures with air. Care shall be taken to ensure that the relevant safety precautions are observed. 0 Introduction In ISO Recommendation 779, published in 1968, a colorimetric method was prescribed for the determina

18、tion of the iron content of pulp. However, in practice, such determinations are frequently made by application of a flame atomic absorption procedure, if the equipment is available. As comparative tests have proved that similar results are obtainable by both methods, this International Standard prov

19、ides guidance on the use of flame atomic absorption spectrometric equipment as an alternative procedure. 1 Scope and field of application This International Standard specifies two methods for the determination of the iron content of pulp, namely a 1,10-phenanthroline photometric method (method A); a

20、 flame atomic absorption spectrometric method (method B). These methods are applicable to all kinds of pulp. 2 References ISO 638, Pulps Determination of dry matter content. ISO 1762, Pulps Determination of ash. 3 Method A: 1,10-Phenanthroline photometric method 3.1 Principle Ashing of the pulp and

21、dissolution of the ash in hydrochloric acid. Reduction of the trivalent iron with hydroxylammonium chloride. Formation of a complex between iron(II) and 1,10-phenanthroline in a buffered medium and photometric measurement of the coloured complex at a wavelength of about 510 nm. 3.2 Reagents During t

22、he analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 3.2.1 Sodium acetate trihydrate (NaCOOCH3.3H2O), 540 g/l solution. 3.2.2 Hydroxylammonium chloride Hydroxylamine hydrochloride (HONH3Cl) 20 g/l solution. 3.2.3 1,10-phenanthroline hy

23、drochloride monohydrate (C12H8N2.HCl.H2O), 10 g/l solution. This reagent may be replaced by the corresponding quantity of 1,10-phenanthroline monohydrate (C12H8N2.H2O). Store the solution away from light. Use only colourless solutions. 3.2.4 Hydrochloric acid, about 6 mol/l solution 3.2.5 Iron, stan

24、dard solution, corresponding to 0,1 g of Fe per litre. Dissolve 0,100 g of pure iron wire in the smallest possible quantity of hydrochloric acid, 1,19 g/ml, in a 1 000 ml one-mark volumetric flask. Dilute to the mark and mix. 1 ml of this standard solution contains 0,1 mg of Fe. 3.2.6 Iron, standard

25、 solution corresponding to 0,01 g of Fe per litre. Transfer 100 ml of the standard iron solution (3.2.5) to a 1 000 ml one-mark volumetric flask, dilute to the mark and mix. 1 ml of this standard solution contains 0,01 mg of Fe. This solution is not stable. 3.3 Apparatus Ordinary laboratory apparatu

26、s and 3.3.1 Spectrophotometer, or 3.3.2 Photoelectric absorptiometer, fitted with filters giving a maximum transmission between 500 and 520 nm and cells provided with lids. 3.3.3 pH meter 3.4 Preparation of the sample Tear the air-dry sample into pieces of a suitable size. Do not use cut or punched

27、edges or other parts where metallic contamination may have occurred. 3.5 Procedure 3.5.1 Number of determinations and determination of dry matter content The determination shall be carried out in duplicate. Simultaneously with the determination, two 10 g test portions shall be taken to determine the

28、 dry matter content in accordance with ISO 638. 3.5.2 Test portion Weigh, to the nearest 0,01 g, about 10 g of the sample. NOTEIf the iron content of the sample is known to exceed 20 mg/kg, take a test portion of 5 g. 3.5.3 Ashing of the test portion Carefully clean a dish of fused silica or platinu

29、m. Remove any spots in the platinum dish by rubbing with fine sand. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 09:02:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4897-3:1983 2 BSI 12-1999 To check that the dish is free from iron, heat in the dish about 2 ml of the hydrochloric acid s

30、olution (3.2.4), diluted with about 10 ml of water. Allow to cool, and add 1 ml of the hydroxylamine hydrochloride solution (3.2.2), 1 ml of the 1,10-phenanthroline hydrochloride solution (3.2.3) and 10 ml of the sodium acetate solution (3.2.1). No red colour shall appear. Ash the test portion in th

31、e dish as specified in ISO 1762. 3.5.4 Blank test Carry out a blank test at the same time as the determination following the same procedure and using the same amounts of all reagents as used for the determination, but omitting the test portion. 3.5.5 Preparation of the calibration graph 3.5.5.1 Prep

32、aration of the standard colorimetric solutions for photometric measurements carried out in cells of 1 cm optical path length. Into each of a series of five 50 ml one-mark volumetric flasks, transfer respectively the volumes of the standard iron solution (3.2.6) shown in Table 1. Table 1 3.5.5.2 Colo

33、ur development Add to each flask 10 ml of the hydrochloric acid solution (3.2.4), 1 ml of the hydroxylammonium chloride solution (3.2.2), 1 ml of the 1,10-phenanthroline hydrochloride solution (3.2.3), 15 ml of the sodium acetate solution (3.2.1). Dilute to the mark, mix and allow to stand for 15 mi

34、n. 3.5.5.3 Photometric measurements Carry out the photometric measurements with the spectrophotometer (3.3.1) at a wavelength of about 510 nm or with the photoelectric absorptiometer (3.3.2) with suitable filters, after having adjusted the instrument to zero absorbance against a compensation solutio

35、n, prepared as given in 3.5.5.1, 3.5.5.2 omitting the standard iron solution (3.2.6). NOTEAvoid exposure of the coloured solution to direct sunlight. 3.5.5.4 Plotting of the calibration graph Plot a graph having, for example, the masses, in milligrams, of iron (contained in 50 ml of standard colorim

36、etric solution) as abscissae and the corresponding values of absorbance as ordinates. 3.5.6 Determination 3.5.6.1 Dissolution of the ash and preparation of the test solution To the ash (3.5.3), add 5 ml of the hydrochloric acid solution (3.2.4) and evaporate to dryness on a steam bath. Repeat this o

37、nce and then treat the residue with another 5 ml portion of the hydrochloric acid and heat for 5 min on the steam bath. With the aid of water, transfer the contents of the dish to a 50 ml one-mark volumetric flask. To ensure complete extraction, add a further 5 ml of the hydrochloric acid solution t

38、o the residue in the dish and heat on the steam bath. With the aid of water, transfer this last portion to the main quantity in the volumetric flask, dilute to the mark and mix. 3.5.6.2 Colour development To the test solution (3.5.6.1), add, in the following order, 1 ml of the hydroxylammonium chlor

39、ide solution (3.2.2), 1 ml of the 1,10-phenanthroline hydrochloride solution (3.2.3) and, to obtain a pH value of 3 to 6, 15 ml of the sodium acetate solution (3.2.1). Dilute to the mark and mix and allow to stand for 15 min. If the solution is turbid, filter through a glass filter or centrifuge. 3.

40、5.6.3 Photometric measurement Carry out the photometric measurement on the test solution after colour development, following the procedure specified in 3.5.5.3, after having adjusted the instrument to zero absorbance against the blank test solution (3.5.4). 3.5.7 Expression of results The iron conte

41、nt, expressed in milligrams per kilogram, is given by the formula where m1is the amount of iron, in milligrams, of the test solution, obtained from the calibration graph (3.5.5.4); m0is the mass, in grams, of the test portion, calculated on an oven-dry basis in accordance with ISO 638. Report the re

42、sult as the mean of the two determinations to the first decimal place. Standard iron solution (3.2.6) Corresponding mass of Fe mlmg 0a0 5,00,05 10,00,10 15,00,15 20,00,20 a Compensation solution. 1 000 m1 m0 - - Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 09:02:54 GMT+00:00 2006, Uncontro

43、lled Copy, (c) BSI BS 4897-3:1983 BSI 12-19993 4 Method B: Flame atomic absorption spectrometric method 4.1 Principle Ashing of the pulp and dissolution of the ash in hydrochloric acid. Aspiration of the test solution into an acetylene-air flame. Measurement of the absorption of the 248,3 nm line em

44、itted by an iron hollow-cathode lamp. 4.2 Reagents During the analysis, use only reagents of recognized analytical reagent grade and only distilled water or water of equivalent purity. 4.2.1 Hydrochloric acid, about 6 mol/l solution. 4.2.2 Iron, 0,01 g/l standard solution as specified in 3.2.6. 4.3

45、Apparatus Ordinary laboratory apparatus and 4.3.1 Atomic absorption spectrometer, fitted with an acetylene and air burner. 4.3.2 Iron hollow-cathode lamp 4.4 Preparation of the sample See 3.4. 4.5 Procedure 4.5.1 Number of determinations and determination of dry matter content See 3.5.1. 4.5.2 Test

46、portion See 3.5.2. 4.5.3 Ashing of the test portion See 3.5.3. 4.5.4 Blank test See 3.5.4. 4.5.5 Preparation of the calibration graph 4.5.5.1 Preparation of the standard matching solutions Into each of a series of five 50 ml one-mark volumetric flasks, place 10 ml of the hydrochloric acid solution (

47、4.2.1) and then, respectively, the volumes of the standard iron solution (4.2.2) shown in Table 2. Dilute to the mark and mix. Table 2 4.5.5.2 Adjustment of the apparatus Fit the hollow-cathode iron lamp (4.3.2) in the apparatus (4.3.1), switch on the current and allow to stabilize. Adjust the curre

48、nt, the sensitivity and the aperture of the slit according to the characteristics of the apparatus. Adjust the wavelength in the region of 248,3 nm to maximum absorbance. Adjust the pressure of the acetylene and of the air according to the characteristics of the burner. Adjust the aspiration rate to

49、 between 2 and 4 ml/min. 4.5.5.3 Spectrometric measurements Aspirate the series of standard matching solutions (4.5.5.1) in succession into the flame and measure the absorbance for each. Take care to keep the aspiration rate constant throughout the preparation of the calibration graph. Spray water through the burner after each measurement. 4.5.5.4 Plotting the graph Plot a graph having, for example, the masses, in milligrams (contained in 50 ml of the standard matching solutions) as abscissae and the corresponding values for the measured a