1、INTERNATIONAL STANDARD ISO 420 Second edition 1994-1 o-1 5 Photography - Processing chemicals - Specifications for potassium bromide Photographie - Produits chimiques de traitement - Spkcifications pour Ie bromure de potassium Reference number ISO 420: II 994(E) ISO 420: 1994(E) Foreword ISO (the In
2、ternational 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 interested in a subject for which a technical committee h
3、as 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 Commission (IEC) on all matters of electrotechnical
4、 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. International Standard ISO 420 was prepared by Technica
5、l Committee lSO/TC 42, Photography. This second edition cancels and replaces the first edition (ISO 420:1976), which has been technically revised. 0 ISO 1994 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electr
6、onrc or mechanrcal, rncluding photocopying and microfilm, without permrssion in writing from the publisher. lnternational Organization for Standardization Case postale 56 l CH-l 211 Geneve 20 l Switzerland Printed in Switzerland 0 ISO ISO 420: 1994(E) Introduction 0.1 This International Standard is
7、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, 3, 5, 6, 7, 8 and 10 of ISO 10349. This International Standard is intended for use by individ
8、uals 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, rubber gloves and other prot
9、ective 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 letter enclosed in angle brack
10、ets, , 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 Chemical and physical re- quire
11、ments 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 to assure sufficient puri
12、ty 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 availability of the higher-
13、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 use. Although the ultimat
14、e 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 satisfactory method is availabl
15、e. 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 tests. All requirements liste
16、d in clause 4 are mandatory. The physical appearance of the material and any footnotes are for general information only and are not part of the requirements. . . . Ill ISO 420:1994(E) 0 ISO 0.3 Efforts have been made to employ tests which are capable of being run in any normally equipped laboratory
17、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 improvements have been made
18、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 the User. In case of disag
19、reement 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 420: 1994(E) Photography - Processing chemicals - Specifications for potassium bromide 1 Scope Thi
20、s International Standard establishes criteria for the purity of photographit-grade potassium bromide and specifies the test methods to be used to determine the purity. 2 Normative references The following International Standards contain pro- visions which, through reference in this text, consti- tut
21、e 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 International Standard are encouraged to investigate the possibility of applying the most recent editions of the
22、Standards indicated below. Members of IEC and ISO maintain registers 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: Det
23、ermi- nation of matter insoluble in ammonium hydroxide solution. ISO 10349-5: 1992, Photography - Photographic- grade chemicals - Test methods - Part 5: Determi- nation of heavy metals and iron content. ISO 10349-6: 1992, Photography - Photographic- grade chemicals - Test methods - Part 6: Determi-
24、nation of halide con tent. ISO 10349-7: 1992, Photography - Photographic- grade chemicals - Test methods - Part 7: Determi- nation of alkalinity or acidity. ISO 10349-8: 1992, Photography - Photographic- grade chemicals - Test methods - Part 8: Determi- nation of volatile matter. ISO 10349-10: 1992,
25、 Photography - Photographic- grade chemicals - Test methods - Part IO: Determi- nation of sulfide tonten t. 3 General 3.1 Physical properties Potassium bromide (KBr) exists in the form of white crystals or a crystalline powder. lt has a relative molecular mass of 119,OO. 3.2 Hazardous properties Pot
26、assium bromide is not hazardous when handled with normal precautions. 3.3 Storage Potassium bromide shall be stored in a closed Container at room temperature. 4 Requirements A summary of the requirements is shown in table 1. 5 Reagents and glassware All reagents, materials and glassware shall confor
27、m 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 information to the user and are not meant to provide conformance with hazard
28、ous 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 Content of KBr shall be between 99,0 % (m/m) min. and 100,3 % (mlm) max. 1 ISO 420:1994(E) 0 ISO Table 1 - Summary of requirements 7.12 Reagents Test Limit Int
29、ernational Subclause Standard in which test method is given Assay 99,0 % (HZ/IPZ) min. 7.1 ISO420 100,3 % (m/m) max. Insoluble matter (as 0,3 % (mlm) max. 7.2 ISO 10349-3 precipitate of Calcium and magnesium in ammonium hydroxide) Heavy metals (as Pb) 0,002 % (-TZ/ITZ) max. 7.3 ISO 10349-5 Iron (Fe)
30、 0,002 % (ITZ/UZ) max. 7,4 ISO 10349-5 Halides (as KCI) 0,50 % (m/m) max. 7.5 ISO 10349-6 Alkaiinity (as KOH) 0,015 % (m/m) max. 7.6 ISO 10349-7 Acidity (as HBr) 0,010 % (m/m) max. 7.7 ISO 10349-7 Volatile matter 0,3 % ( c2 is the actual concentration, expressed in moles per litre, of the ammonium t
31、hiocyanate (7.1.2.4); V is the volume, in millilitres, of the ammonium thiocyanate (7.1.2.4) used to resch the titration endpoint; 1) Hazard warning Codes are defined in ISO 10349-1. 2) This solution may be prepared from nitric acid, 69 % (m/m) (DANGER:). 3) Commercially available Standard reagent i
32、s recommended. If the soiution is to be prepared, see any quantitative analytical chemistry text. 2 0 ISO m is the mass, in grams, of the test Portion; 7.5 Halide content 7.51 Specification Maximum content of Cl- (0,50 % as KCI). 7.5.2 Reagents 11,90 is the conversion factor obtained from the mass o
33、f potassium bromide equivalent to 1 mole of silver nitrate (i.e. 119,O) x the conversion factor for millilitres to litres (i.e. 0,001) x 100 (for percentage). halides shall be 0,25 % (mhd as NOTE 1 The assay Iimit is based on materials as received and is not corrected for potassium chloride content.
34、 The presence of potassium chloride will increase the assay value; i.e. 1 g of potassium chloride is equivalent to 1,6 g of potassium bromide. 7.5.2.1 Nitrit acid, HNO3 (1+2) (DANGER: )l) 2). 7.5.2.2 Hydrogen Peroxide, Hz02 (DANGER: cCxO), approximately 167 g/l) (1 + 1). 7.2 Insoluble matter content
35、 (as a precipitate of Calcium and magnesium in ammonium hydroxide) Dilute 30 % hydrogen peroxide (DANGER: CO) with an equal volume of water. 7.2.1 Specification 7.5.3 Procedure Maximum content of insoluble matter shall be 0,3 % (mlm). Weigh, to the nearest 0,Ol g, a test Portion of 1 g and dissolve
36、it in 15 ml of the nitric acid (7.5.2.1) (4x0) in a conical flask. Add 6 ml of the hydrogen peroxide (7.5.2.2) (cC) and digest on a steam bath until the Solution is colourless. Wash down the sides of the flask with water, digest for an additional 15 min and dilute to 250 ml with water. 7.2.2 Procedu
37、re Determine the percentage of insoluble matter in ac- cordante with ISO 10349-3. 7.3 Heavy metals 7.3.1 Specification Maximum content 0,002 % (m/m). content (as Pb) of heavy metals shall be 7.3.2 Procedure NOTE 2 The Standard for the iron test (7.4) is prepared in Transfer a 25 ml aliquot of the te
38、st Solution into a 100 ml beaker. Pipette a 25 ml Portion of the halide Standard A in accordance with sentence 3 of clause 7 of ISO 10349-6:1992 and then continue in accordance with the rest of the procedure. 7.6 Alkalinity (as KOH) 7.6.1 Specification the Same way as the heavy metals Standard. Maxi
39、mum free alkali content shall be 0,015 % (m/m). Determine the percentage of heavy metals in accord- ante 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, 7.2. Use 10 ml of the heavy metals Standard prepared in accordance with ISO 10
40、349-5: 1992, 8.1 .l. 7.6.2 Procedure Prepare a test Solution in accordance with ISO 10349-7 using a test Portion of 3,9 g to 4,l g. If the prepared test Solution turns pink when the indicator is added, determine the percentage alkalinity as potassium hydroxide using a factor K equal to 5,61 in the c
41、alculation given in ISO 10349-7. 7.4 Iron content 7.7 Acidity (as HBr) 7.4.1 Specification 7.7.1 Specification Maximum content of iron shall be 0,002 % (m/m). Maximum free acid content shall be 0,010 % (m/m). 7.4.2 Procedure 7.7.2 Procedure Determine the percentage of iron in accordance with ISO 103
42、49-5. Use a test Portion of 4,90 g to 5,lO g of the Sample prepared in accordance with ISO 10349-5:1992, 7.2. Use 10 ml of the iron Standard prepa red in accordance with ISO 10349-5: 1992, 8.1.1. If the prepared test Solution in the alkalinity deter- mination remains clear when the indicator is adde
43、d, determine the percentage acidity as hydrobromic acid in accordance with ISO 10349-7. Use a factor K equal to 8,09 in the calculation given in ISO 10349-7. 3 ISO 420:1994(E) 0 ISO 7.8 Volatile matter 7.8.1 Specification Maximum percentage of volatile matter shall be 0,3 % (m/m). 7.82 Procedure Det
44、ermine the percentage of volatile matter in ac- cordante with ISO 10349-8. Use a test Portion of about 5,0 g, weighed to the nearest 0,000 1 g, and heat in an oven at 105 “C+ 5 “C for 4 h. 7.9 Sulfide content 7.9.1 Specification Maximum content 0,000 24 % (ITZ/LIZ) as SZ- of sulfides shall be (0,000
45、 8 % as K,S). Determine the percentage of sulfides in accordance 7.9.2 Procedure with ISO 10349-10. Use a test Portion of 1,90 g to 210 g, and mix with 40 ml of water. Use a 5 ml Portion of the sulfide Standard. 7.10 Iodide content 7.10.1 Specification To pass test. 7.10.2 Reagents 7.10.2.1 Carbon t
46、etrachloride (CCI,) or chloroform (CHCl$ (DANGER:)! 7.10.2.2 Sulfuric acid, H2S04 (1 + 9)? 7.10.2.3 Iron(lll) chloride, FeCls, 100 g/l. Dissolve 100 g of iron(lll) chloride hexahydrate (FeCl3.6H20) in 800 ml of water and dilute to 1 litre. (7.1023) and 1 ml of the carbon tetrachloride or chloroform
47、(7.10.2.1) (CB). 7.1 1.2.2 Potassium iodide, KI. 7.11.2.3 Sulfuric acid, H2S04 (1 + 9)5! 7.11.3 Procedure Weigh, to the nearest 0,l g, a test Portion of about 10 g and dissolve it in 10 ml of water in a test tube. Treat this Solution, and 10 ml of water in a second test tube (control), in the follow
48、ing manner. Add 0,5 g of potassium iodide (7.11.2.2), 1 ml of sulfuric acid (7.1123) and 1 ml of the carbon tetrachloride or chloroform (7.11.2.1) (). Stopper the test tube and Shake the mixture vigorously. Allow the layers to separate. Compare, in the test tubes, the colours produced in the organic
49、 layers of the test and control samples. The Sample shall be no greater in colour than the control Sample. 7.12 Appearance of solution 7.12.1 Specification The Solution shall be clear and free from insoluble matter except for a slight flocculence. MO.3 Procedure 7.12.2 Procedure Weigh, to the nearest 0,l g, a test Portion of about 10 g and dissolve it in 25 ml of water. Add 1 ml of the sulfuric acid (7.10.2.2), 0,5 ml of the iron(lll) chloride Dissolve a test Portion of 20 g in 100 ml of water. Observe the Solution for colour and clarity. 4) Concern over the use of halogenated hydrocarbon
