1、BRITISH STANDARD BS ISO 418:2001 Photography Processing chemicals Specifications for anhydrous sodium sulfite ICS 37.040.30 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBS ISO 418:2001 This British Standard, having been prepared under the direction of the Consumer Products a
2、nd Services Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 25 January 2002 BSI 25 January 2002 ISBN 0 580 37506 4 National foreword This British Standard reproduces verbatim ISO 418:2001 and implements it as the UK national standard
3、. It supersedes BS ISO 418:1994 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee CPW/42, Photography, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references T
4、he British Standards which implement international publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Sta
5、ndard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the r
6、esponsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front
7、 cover, the ISO title page, pages ii to v, a blank page, pages 1 to 7 and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments Reference number ISO 418:2001(E) ISO 2001INTERNATIONAL STA
8、NDARD ISO 418 Third edition 2001-12-15 Photography Processing chemicals Specifications for anhydrous sodium sulfite Photographie Produits chimiques de traitement Spcifications relatives au sulfite de sodium anhydre ii ISO 418:2001(E) iiiContents Page Foreword.iv Introduction.v 1 Scope 1 2 Normative
9、references1 3 General1 3.1 Physical properties1 3.2 Hazardous properties1 3.3 Storage1 4 Requirements.2 5 Reagents and glassware.2 6 Sampling.2 7 Test methods .2 7.1 Assay 2 7.2 Mass fraction of insoluble matter (as a precipitate of calcium, magnesium and ammonium hydroxides) 5 7.3 Mass fraction of
10、heavy metals .5 7.4 Mass fraction of iron .5 7.5 Alkalinity (as Na 2 CO 3 )5 7.6 Reaction to ammoniacal silver nitrate.6 7.7 Mass fraction of thiosulfate (as Na 2 S 2 O 3 )6 7.8 Appearance of solution.7 Table 1 Summary of requirements .2 ISO 418:2001(E) iv Foreword ISO (the International Organizatio
11、n 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. Each member body interested in a subject for which a technical committee has been established has
12、 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 Commission (IEC) on all matters of electrotechnical standardization. Inter
13、national Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. 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 me
14、mber bodies casting a vote. Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. International Standard ISO 418 was prepared by Technical Co
15、mmittee ISO/TC 42, Photography. This third edition cancels and replaces the second edition (ISO 418:1994), of which it constitutes a technical revision. ISO 418:2001(E) vIntroduction This International Standard is one of a series that establishes criteria of purity for chemicals used in processing p
16、hotographic materials. General test methods and procedures cited in this International Standard are compiled in ISO 10349-1. This International Standard is intended for use by individuals with a working knowledge of analytical techniques, which may not always be the case. Some of the procedures util
17、ize caustic, toxic, or otherwise hazardous chemicals. Safe laboratory practice for the handling of chemicals requires the use of safety glasses or goggles and, in some cases, other protective apparel such as rubber gloves, face masks or aprons. Normal precautions for the safe performance of any chem
18、ical procedure shall be exercised at all times, but specific details have been provided for hazardous materials. Hazard warnings designated by a letter enclosed in angle brackets, , are used as a reminder in those steps detailing handling operations and are defined in ISO 10349-1. More detailed info
19、rmation regarding hazards, handling and use of these chemicals may be available from the manufacturer. This International Standard provides chemical and physical requirements for the suitability of a photographic-grade chemical. The tests correlate with undesirable photographic effects. Purity requi
20、rements are set as low as possible consistent with these photographic effects. These criteria are considered to be the minimum requirements necessary to assure sufficient purity for use in photographic processing solutions, except that if the purity of a commonly available grade of chemical exceeds
21、photographic processing requirements and if there is no economic penalty in its use, the purity requirements have been set to take advantage of the availability of the higher-quality material. Every effort has been made to keep the number of requirements to a minimum. Inert impurities are limited to
22、 amounts that will not unduly reduce the assay. All tests are performed on samples “as received” to reflect the condition of materials furnished for use. Although the ultimate criterion for suitability of such a chemical is its successful performance in an appropriate use test, the shorter, more eco
23、nomical test methods described in this International Standard are generally adequate. Assay procedures have been included in all cases where a satisfactory method is available. An effective assay requirement serves not only as a safeguard of chemical purity, but also as a valuable complement to the
24、identity test. Identity tests have been included whenever a possibility exists that another chemical or mixture of chemicals could pass the other tests. All requirements listed in clause 4 are mandatory. The physical appearance of the material and any footnotes are for general information only and a
25、re not part of the requirements. Efforts have been made to employ tests that are capable of being run in any normally equipped laboratory and, whenever possible, to avoid tests that require highly specialized equipment or techniques. Instrumental methods have been specified only as alternative metho
26、ds or alone in those cases where no other satisfactory method is available. Over the past few years, great improvements have been made in instrumentation for various analyses. Where such techniques have equivalent or greater precision, they may be used in place of the tests described in this Interna
27、tional Standard. Correlation of such alternative procedures with the given method is the responsibility of the 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
28、. blankINTERNATIONAL STANDARD ISO 418:2001(E)1Photography Processing chemicals Specifications for anhydrous sodium sulfite 1 Scope This International Standard establishes criteria for the purity of photographic-grade anhydrous sodium sulfite and specifies the tests to be used to determine the purity
29、. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agre
30、ements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registe
31、rs of currently valid International Standards. ISO 10349-1:1992, Photography Photographic-grade chemicals Test methods Part 1: General. ISO 10349-3:1992, Photography Photographic-grade chemicals Test methods Part 3: Determination of matter insoluble in ammonium hydroxide solution. ISO 10349-5:1992,
32、Photography Photographic-grade chemicals Test methods Part 5: Determination of heavy metals and iron content. ISO 10349-7:1992, Photography Photographic-grade chemicals Test methods Part 7: Determination of alkalinity or acidity. ISO 10349-9:1992, Photography Photographic-grade chemicals Test method
33、s Part 9: Reaction to ammoniacal silver nitrate. 3 General 3.1 Physical properties Anhydrous sodium sulfite (Na 2 SO 3 ) is a white granular powder. It has a relative molecular mass of 126,04. 3.2 Hazardous properties Anhydrous sodium sulfite is not hazardous when handled with normal precautions. Av
34、oid contact with acids. 3.3 Storage Anhydrous sodium sulfite shall be stored in a closed container at room temperature. ISO 418:2001(E) 2 4 Requirements A summary of the requirements is shown in Table 1. Table 1 Summary of requirements Test Limit Subclause International Standard in which test method
35、 is given Assay Minimum: 97,0 % 7.1 ISO 418 Insoluble matter (as precipitate of calcium, magnesium and ammonium hydroxides) Maximum: 0,5 % 7.2 ISO 10349-3 Mass fraction of heavy metals (as Pb) Maximum: 0,002 % 7.3 ISO 10349-5 Mass fraction of iron (Fe) Maximum: 0,005 % 7.4 ISO 10349-5 Alkalinity (as
36、 Na 2 CO 3 ) Maximum: 0,15 % 7.5 ISO 10349-7 Reaction to ammoniacal silver nitrate To pass test 7.6 ISO 10349-9 Mass fraction of thiosulfate (as Na 2 S 2 O 3 ) Maximum: 0,03 % 7.7 ISO 418 Appearance of solution Clear and free from insoluble matter except for a slight flocculence 7.8 ISO 418 5 Reagen
37、ts and glassware All reagents, materials and glassware 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 handling operations, are defined in ISO 10349-1. These symbols are used to provide informa
38、tion 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 7.1.1 Specification The minimum mass fraction of anhydrous sodium sulfite shall be 97,0 %. ISO 418:2001(E) 37.1
39、.2 Reagents 7.1.2.1 Hydrochloric acid, HCI, r 1,18 g/ml (DANGER: BC) 1) . 7.1.2.2 Potassium iodide, KI. 7.1.2.3 Iodine, c(I 2 ) = 0,05 mol/l (12,7 g/l) 2)3) . Weigh, to the nearest 0,001 g, 12,7 g of freshly sublimed iodine (DANGER: CO) into a tared weighing flask. Add 36 g of potassium iodide (7.1.
40、2.2) and 100 ml of water. After solution is complete, add three drops of hydrochloric acid (7.1.2.1) (DANGER: BC), and dilute to 1 litre at 20 C in a volumetric flask. From the mass of iodine, m, calculate the concentration, c, in moles per litre, from ( ) 2 I 254 m c = 7.1.2.4 Sodium thiosulfate, c
41、(Na 2 S 2 O 3 ) = 0,100 mol/l (15,8 g/l) 2) . NOTE This solution is not required for the direct-titration method (7.1.4.2). 7.1.2.5 Salicylic acid, c(HOC 6 H 4 COOH) = 1 % (10 g/l). 7.1.2.6 Starch indicator, 5 g/l solution. Stir 5 g of soluble starch into 100 ml of 1 % salicylic acid solution (7.1.2
42、.5). Add 300 ml to 400 ml of boiling water. Boil until the starch dissolves and dilute to 1 litre with water. 7.1.3 Apparatus 7.1.3.1 Burette, of capacity 50 ml. 7.1.3.2 Pipette, of capacity 50 ml. 7.1.3.3 Magnetic stirrer and bar, for the direct-titration method (7.1.4.2). 7.1.4 Procedure Use eithe
43、r the back-titration method (7.1.4.1) or the direct-titration method (7.1.4.2). 7.1.4.1 Back-titration method Using a pipette (7.1.3.2), transfer 50,00 ml of the iodine solution (7.1.2.3) to a glass-stoppered flask. Weigh, to the nearest 0,000 1 g, a test portion of about 0,25 g and wash this into t
44、he flask. Add 5 ml of the hydrochloric acid (7.1.2.1) (DANGER: BC) and using a burette (7.1.3.1) titrate with the sodium thiosulfate solution (7.1.2.4), adding 2 ml of the starch indicator (7.1.2.6) just before the endpoint. 1) Hazard warning codes are defined in ISO 10349-1. 2) Commercially availab
45、le analysed reagent solution is recommended. If the solution is to be prepared, see any quantitative analytical chemistry test. 3) It is recommended that self-prepared iodine solutions be standardized before use. ISO 418:2001(E) 4 7.1.4.2 Direct-titration method Weigh, to the nearest 0,000 1 g, a te
46、st portion of about 0,16 g. Using a pipette (7.1.3.2), transfer 50,00 ml of the iodine solution (7.1.2.3) to a completely dry 250 ml beaker that contains a magnetic stirring bar (7.1.3.3). While stirring the iodine solution in the beaker, add the test portion to the centre of the beaker using a came
47、l-hair brush. Avoid contact of the sample with the sides of the beaker. If the iodine is not decolourized after addition of the sample, discard the trial and restart the procedure. If necessary, increase the test portion by 0,01 g. Wash down the side walls of the beaker using about 2 ml of the starc
48、h indicator (7.1.2.6). Using a burette (7.1.3.1), immediately titrate with the iodine solution to the first permanent light-purple colour. Wash any iodine solution remaining on the burette tip into the solution with deionized water. If the titration exceeds 10 ml, repeat the test as this can result
49、in test results lower than the actual assay. Adjust the sample appropriately. 7.1.5 Expression of results 7.1.5.1 Back-titration method The assay, expressed as a percentage by mass of sodium sulfite (Na 2 SO 3 ), is given by ( ) ( ) 12 6,302 100ccV m - where c 1 is the actual concentration, expressed in moles per litre, of the iodine solution (7.1.2.3); c 2 is the actual concentration, expressed in moles per litre, of the sodium thiosulfate solution (7.1.2.4); V is the volume, expressed in millilitres,
