1、INTERNATIONAL STANDARD Second edition 1994-10-15 Photography - Processing chemicals - Specifications for anhydrous sodium carbonate and sodium carbonate monohydrate Photographie - Produits chimiques de traitement - Spkifications pour Ie carbonate de sodium anhydre et monohydrate Reference number ISO
2、 424:1994(E) ISO 424: 1994(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national Standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Esch member body interes
3、ted in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical C
4、ommission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Inter
5、national Standard ISO 424 was prepared by Technical Committee ISOflC 42, Photography. This second edition cancels and replaces the first edition (ISO 424:1976) and ISO 3942:1976. 0 ISO 1994 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in
6、any form or by any means, electronie or mechanical, including photocopying and microfilm, without Permission in writing from the publisher. International Organization for Standardization Case postale 56 l CH-121 1 Geneve 20 l Switzerland Printed in Switzerland ii 0 ISO ISO 424: 1994(E) Introduction
7、0.1 This International Standard is one of a series that establishes criteria of purity for chemicals used in processing photographic materials. General test methods and procedures cited in this International Standard are compiled in Parts 1, 5, 6 and 9 of ISO 10349. This International Standard is in
8、tended for use by individuals with a working knowledge of analytical techniques, which may not always be the case. Some of the procedures utilize caustic, toxic or otherwise hazardous chemicals. Safe laboratory practice for the handling of chemicals requires the use of safety glasses or goggles, rub
9、ber gloves and other protective apparel such as face masks or aprons where appropriate. Normal precautions required in the Performance of any Chemical procedure are to be exercised at all times but care has been taken to provide warnings for hazardous materials. Hazard warnings designated by a lette
10、r enclosed in angle brackets, , are used as a reminder in those Steps detailing handling operations and are defined in ISO 10349-1. More detailed information regarding hazards, handling and use of these chemicals may be available from the manufacturer. 0.2 This International Standard provides Chemic
11、al and physical re- quirements for the suitability of a photographit-grade Chemical. The tests correlate with undesirable photographic effects. Purity requirements are set as low as possible consistent with these photographic effects. These criteria are considered the minimum requirements necessary
12、to assure sufficient purity for use in photographic processing solutions, except that if the purity of a commonly available grade of Chemical exceeds photographic processing requirements and if there is no economic penalty in its use, the purity requirements have been set to take advantage of the av
13、ailability of the higher-quality material. Every effort has been made to keep the number of requirements to a minimum. Inert impurities are limited to amounts which will not unduly reduce the assay. All tests are performed on samples “as received” to reflect the condition of materials furnished for
14、use. Although the ultimate criterion for suitability of such a Chemical is its successful Performance in an appropriate use test, the shorter, more economical test methods described in this International Standard are generally adequate. Assay procedures have been included in all cases where a satisf
15、actory method is available. An effective assay requirement serves not only as a safeguard of Chemical purity but also as a valuable complement to the identity test. Identity tests have been included whenever a possibility exists that another Chemical or mixture of chemicals could pass the other test
16、s. All requirements listed in clause 4 are mandatory. The physical appearance of thematerial and any footnotes are for general Information only and are not part of the requirements. . . . Ill ISO 424:1994(E) 0 ISO 0.3 Efforts have been made to employ tests which are capable of being run in any norma
17、lly equipped laboratory and, wherever possible, to avoid tests which require highly specialized equipment or techniques. Instru- mental methods have been specified only as alternative methods or alone in those cases where no other satisfactory method is available. Over the past few years, great impr
18、ovements have been made in instru- mentation for various analyses. Where such techniques have equivalent or greater precision, they may be used in place of the tests described in this International Standard. Correlation of such alternative procedures with the given method is the responsibility of th
19、e User. In case of disagreement in results, the method called for in the specification shall prevail. Where a requirement states “to pass test”, however, alternative methods shall not be used. INTERNATIONAL STANDARD o Iso ISO 424:1994(E) Photography - Processing chemicals - Specifications for anhydr
20、ous sodium carbonate and sodium carbonate monohydrate 1 Scope This International Standard establishes criteria for the purity of photographit-grade anhydrous sodium car- bonate and sodium carbonate monohydrate and speci- fies the test methods to be used to determine the purity. 2 Normative reference
21、s The following International Standards contain pro- visions which, through reference in this text, consti- tute provisions of this International Standard. At the time of publication, the editions indicated were valid. All Standards are subject to revision, and Parties to agreements based on this In
22、ternational Standard are encouraged to investigate the possibility of applying the most recent editions of the Standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 10349-1: 1992, Photography - Photographic- grade chemicals - Test method
23、s - Part 7: General. ISO 10349-5: 1992, Photography - Photographic- grade chemicals - Test methods - Part 5: Determi- nation of heavy metals and iron con ten t. ISO 10349-6: 1992, Photography - Photographic- grade chemicals - Test methods - Part 6: Determi- nation of halide content. ISO 10349-9: 199
24、2, Photography - Photographic- grade chemicals - Test methods - Part 9: Reaction to ammoniacal silver nitra te. 3 General 3.1 Physical properties Anhydrous sodium carbonate, NazC03, exists in the form of white granules or powder. lt has a relative molecular mass of %05,99. Sodium carbonate monohydra
25、te, Na2C03.H20s exists in the form of white crystalline granules. lt has a relative molecular mass of 124,OO. 3.2 Hazardous properties Sodium carbonate is not hazardous when handled with normal precautions. 3.3 Handling and storage Sodium carbonate shall be stored in a closed Container at room tempe
26、rature. 4 Requirements A summary of the requirements is sf- 5 Reagents and glassware All reagents, materials and glasswar lown in table 1. 3 shall conform to the requirements specified in ISO 10349-1 unless otherwise noted. The hazard warning Symbols used as a reminder in those Steps detailing handl
27、ing operations are defined in ISO 10349-1. These Symbols are used to provide information to the user and are not meant to provide conformance with hazardous labelling requirements, as these vary from country to country. 6 Sampling See ISO 10349-1. 7 Test methods 7.1 Assay 7.1 .l. Specifications Cont
28、ent of anhydrous sodium carbonate, Na2C03 ” shall be 98,O % (uz/) min. Content of sodium carbonate monohydrate, Na2C03.H201 shall be 98,5 % (/IIz) min. 1 ISO 424: 1994(E) 0 ISO Table 1 - Summary of requirements Test Limit Subclause Assay anhydrous monohydrate Heavy metals (as Pb) Iran (Fe) Halides (
29、as Cl) anhydrous monohydrate Reaction to ammoniacal siver nitrate Free alkali (as NaOH) anhydrous monohydrate Bicarbonate (as NaHCO,) anhydrous monohydrate Appearance of Solution I NOTE - m/rn = mass/mass 98,0 % (WZ/VZ) min. 98,5 % (mlm) min. 0,001 % (17+2) max. 0,002 % (m/m) max. 0,35 % (WZ/WZ) max
30、. 0,30 % (HZ/OZ) max. To pass test 0,20 % (I 7.1.5 Expression of results The assay, expressed as a percentage by mass, for anhydrous sodium carbonate (Na$O$, is given by m is the mass, in grams, of the test Portion; 5,30 is a conversion factor obtained from the mass of anhydrous sodium carbonate equ
31、ivalent to 1 mole of hydrochloric acid (i.e. 53,0) x the conversion factor for millilitres to litres (i.e. 0,001) x 100 (for percentage); is the actual concentration, expressed in moles per litre, of the hydrochloric acid (7.1.2.1); 1) Hazard wart-ring Codes are defined in ISO 10349-1. 2) Commercial
32、ly available analysed reagents are recommended. lf soiutions are to be prepared, see any quantitative analytical chemistry text. 3) This tan be prepared from hydrochloric acid, p = 1 ,18 g/l (DANGER:). 2 0 ISO ISO 424:1994(E) 620 is a conversion factor obtained from the mass of sodium carbonate mono
33、hydrate equivalent to 1 mole of hydrochloric acid Solution (i.e. 620) x the conversion factor for millilitres to litres (i.e. 0,001) x 100 (for percentage). 7.5 Reaction to ammoniacal silver nitrate 7.5.1 Specification To pass test. 7.52 Procedure 7.2 Heavy metals content Determine the reaction to a
34、mmoniacal silver nitrate in accordance with ISO 10349-9. 72.1 Specification Maximum content of heavy metals shall be 0,001 % (m/m). 7.6 Free alkali content (as NaOH) 7.6.1 Specifications 7.22 Procedure Maximum free alkali content in anhydrous sodium car- bonate, NazC03, shall be 0,20 % (vz/). NOTE 1
35、 The Standard for the iron test (7.3) is prepared in the same way as the heavy metals Standard. Maximum free alkali content in sodium carbonate monohydrate, Na2C03.H201 shall be 0,17 % (mlm). Determine the percentage of heavy metals in accord- ante with ISO 10349-5. Use a test Portion of 4,90 g to 5
36、10 g of the Sample prepared in accordance with ISO 10349-51992, 7.3. Use 5 ml of the heavy metals Standard prepared in accordance with ISO 103495: 7.62 Reagents 7.6.2.i Barium chloride, BaClz, neutral solution, 1 mol/l. 8.1.2. 1992, . 3 7.3.1 Maxir 7.3.2 Dissolve 244 g of barium chloride dihydrate (
37、BaCl2.2H20) (DANGER:)j) in 1 litre of carbon- dioxide-free water. Check that it is neutral to phenol- phthalein indicator Solution (7.6.2.6) and, if not, adjust with a few drops of sodium hydroxide Solution (7.6.2.3). ran content Specification jurn content of iron shall be 0,002 % (m/m). 7.6.2.2 Hyd
38、rochlorit acid, HCI I 0,100 mol/1 (3,65 g/l)2 3). Procedure Determine the percentage of iron in accordance with ISO 10349-5. Use a test Portion of 4,90 g to 5,lO g of the Sample prepared in accordance with ISO 10349-5:1992, 7.3. Use IO ml of the iron Standard prepared in accordance with ISO 10349-5:
39、1992, 8.1.2. 7.6.2.3 Sodium hydroxide, NaOH, 0,100 mol/1 (4,O g/l)Z) 4, . 7.6.2.4 Ethanol, C2H50H, 95 % (denatured). 7.6.2.5 Phenolphthalein indicator, ethanol/water Solution, 5 g/l. 7.4 Halide content (as Cl) Dissolve 0,5 g of phenolphthalein in 50 ml of ethanol (7.6.2.4) and add 50 ml of water wit
40、h constant stirring. Filter if necessary. 7.4.1 Specifications Maximum halide content in anhydrous sodium carbon- ate, Na2C03, shall be 0,35 % (I c is the actual concentration, expressed in moles per litre, of the hydrochloric acid (7.6.2.2); V is the volume hyd rox de used , in mil lilitres, itrati
41、on of the sodium for the t V is the vo lume, used for the tit in millilitres, of hydrochloric acid ration; m is the mass, in grams, of the test Portion; m is the mass, in grams, of the test Portion; 8,4 is a conversion factor obtained from the mass of sodium bicarbonate equivalent to 1 mole of hydro
42、chloric acid (i.e. 84,O) x the conversion factor for millilitres to litres (i.e. 0,001) x 100 (for percentage). 4,O is a conversion factor obtained from the mass of sodium hydroxide equivalent to 1 mole of hydrochloric acid (i.e. 40,O) x the conversion factor for millilitres to litres (i.e. 0,001) x
43、 100 (for percentage.). A maximum bicarbonate content (as NaHC03) of 0,7 % for anhydrous sodium carbonate is equivalent to no more than 1,7 ml of the sodium hydroxide (7.6.2.3) used to produce a faint pink colour persisting for 30 s. A maximum free alkali content (as NaOH) of 0,20 % for anhydrous so
44、dium carbonate is equivalent to no more than 1 ,O ml of the hydrochloric acid (7.6.2.2) used to discharge the pink colour. A maximum bicarbonate content (as NaHC03) of 0,6 % for sodium carbonate monohydrate is equivalent to no more than 1,5 ml of the sodium hydroxide (7.6.2.3) used to produce a fain
45、t pink colour persisting for 30 s. A maximum free alkali content (as NaOH) of 0,17 % sodium carbonate monohydrate is equivalent to no more than 0,85 ml of the hydrochloric acid (7.6.2.2) used to discharge the pink colour. 7.7 Bicarbonate content 7.8 Appearance of Solution 7.7.1 Specifications 7.8.1
46、Specification Maximum bicarbonate content, as NaHC03, in an- hydrous sodium carbonate, Na2C03, shall be 0,7 % (mlm). The Solution shall be clear and free from insoluble matter except for a slight flocculence. Maximum bicarbonate as NaHCO, in sodium carbon- ate monohydrate, Na2C03-H201 shall be 0,6 %
47、 (m/m). 7.8.2 Procedure 7.7.2 Reagents For anhydrous sodium carbonate, dissolve 200 g of the Sample in 1 litre of water and examine for colour and clarity. As specified in 7.6.2. 7.7.3 Apparatus For sodium carbonate monohydrate, dissolve 235 g of the Sample in 1 litre 0% water and examine for colour and clarity. As specified in 7.6.3. 4
