1、INTERNATIONAL STANDARD Second edition 1996-I O-l 5 Photography - Processing chemicals - Specifications for potassium thiocyanate Photographie - Produits chimiques de traitemen t - Spbifica tions rela ties au thiocyana te de potassium Reference number IS0 3626:1996(E) IS0 3626: 1996(E) Foreword IS0 (
2、the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical commi
3、ttee 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. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotec
4、hnical 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 IS0 3626 was prepared by T
5、echnical Committee ISO/TC 42, Photography. This second edition cancels and replaces the first edition (IS0 3626:1976), which has been technically revised. 0 IS0 1996 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means
6、, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case Postale 56 l CH-1211 Geneve 20 l Switzerland Printed in Switzerland ii IS0 IS0 3626: 1996(E) Introduction 0.1 This International Sta
7、ndard 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 and 6 of IS0 10349. This International Standard is intended for use by individuals
8、 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 protecti
9、ve 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 brackets
10、“( )” are used as a reminder in those steps detailing handling operations and are defined in IS0 10349-I. 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 requiremen
11、ts for the suitability of a photographic-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 purity
12、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-qua
13、lity 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 ultimate c
14、riterion 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 available.
15、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 listed i
16、n 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. IS0 3626: 1996(E) IS0 0.3 Efforts have been made to employ tests which are capable of being run in any normally equipped laboratory and, wherever
17、 possible, to avoid tests which require highly specialized equipment or techniques. Instrumental 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 in instrumentat
18、ion 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 disagreement in result
19、s, the method called for in the specification shall prevail. Where a requirement states “to pass test”, however, alternative methods shall not be used. iv INTERNATIONAL STANDARD IS0 IS0 3626:1996(E) Photography - Processing chemicals - Specifications for potassium thiocyanate I Scope This Internatio
20、nal Standard establishes criteria for the purity of photographic-grade potassium thiocyanate and specifies the test methods to be used to determine the purity. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this Inter
21、national 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 standards indicated below.
22、 Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 10349-I : 1992, Photography - Photographic-grade chemicals - Test methods - Part I: General. IS0 10349-5: 1992, Photography - Photographic-grade chemicals - Test methods - Part 5: Determination of heavy metals
23、 and iron con tent. IS0 10349-6: 1992, Photography - Photographic-grade chemicals - Test methods - Part 6: Determination of halide con tent. 3 General 3.1 Physical properties Potassium thiocyanate (KCNS) exists as colourless, deliquescent crystals. It has a relative molecular mass of 97,18. 3.2 Haza
24、rdous properties Potassium thiocyanate presents no special hazardous problems under normal handling. 3.3 Storage Store in a cool dry place. Care shall be taken to avoid conditions of high heat and/or humidity which can cause decomposition and emission of toxic fumes. IS0 3626: 1996(E) 4 Requirements
25、 A summary of the requirements is shown in table 1. 5 Reagents and materials, including glassware All reagents, materials and glassware shall conform to the requirements specified in IS0 10349-I unless otherwise noted. The hazard warning symbols used as a reminder in those steps detailing handling o
26、perations are defined in IS0 10349-I. 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 IS0 10349-I. 7 Test procedures 7.1 Assay 7.1.1 Specification Content o
27、f KCNS shall be 98,0 % (m/m) min. Table 1 - Summary of requirements Test Limit Subclause International Standard in which test method is given Assay 98,0 % (LIZ/) min. 7.1 IS0 3626 Heavy metals content (as Pb) 0,002 % (ITZ/ITZ) max. 7.2 IS0 10349-5 Iron content 0,000 2 % ( V is the volume, in millili
28、tres, of the ammonium thiocyanate (7.1.2.4) used for the titration; m is the mass, in grams, of the test portion; 50 is the volume, in millilitres, of silver nitrate added (7.1.4); 9,718 is the conversion factor obtained from the mass of potassium thiocyanate equivalent to 1 mole of silver nitrate (
29、i.e. 97,18) x the conversion factor for millilitres to litres (i.e. 0,001) x 100 (for percentage). Heavy metals content 7.2.1 Specification Maximum content of heavy metals shall be 0,002 % (m/m). 1) This solution may be prepared from concentrated nitric acid, 69 % (mlm) (approx.) (DANGER: (C)(B)(O).
30、 (Hazard warning codes are defined in IS0 10349-I .) 2) are Commercially a available in any vailab quant le ana itative lysed reagent analysis text. solutions are recommended. Procedures for the preparation of these materials 3) This solution may be prepared from solid silver nitrate (DANGER: (C). 3
31、 IS0 3626: 1996(E) IS0 7.2.2 Procedure NOTE - The standard for the iron test (7.3) is prepared in the same way as the heavy metals standard. Determine the percentage of heavy metals in accordance with IS0 10349-5. Use a test portion of I,90 g to 2,10 g, prepared in accordance with IS0 10349-5:1992,
32、7.2. Use 4 ml of the heavy metals standard prepared in accordance with IS0 10349-5:1992, 8.1 .I. 7.3 Iron content 7.3.1 Specification Maximum content of iron shall be 0,0002 % (m/m). 7.3.2 Procedure Determine the percentage of iron in accordance with IS0 10349-5. Use a test portion of 9,90 g to IO,1
33、 0 g, prepared in accordance with IS0 10349-5:1992, 7.2. Use 2 ml of the iron standard prepared in accordance with IS0 10349-5: 1992, 8.1.1. 7.4 Halide content (as Cl-) 7.4.1 Specification Maximum content of halide shall be 0,05 % (m/m) O,l % (m/m) as KCI. 7.4.2 Reagents 7.4.2.1 Sodium hydroxide, so
34、lid (DANGER: (C). 7.4.2.2 Hydrogen peroxide (H202), 67 g/l (approx.) solution. Dilute 1 volume of 30 % hydrogen peroxide (DANGER: (C)(O) with 4 volumes of water. 7.4.3 Procedure Weigh, to the nearest 0,l g, a test portion of about 1 g and dissolve it in 30 ml of the hydrogen peroxide (7.4.2.2). Add
35、1 g of sodium hydroxide (7.4.2.1) (DANGER: (C) and swirl until the vigorous reaction ceases. Add another 30 ml of hydrogen peroxide (7.4.2.2) and boil for 2 min. Cool and dilute to 100 ml with water. Use a 10 ml aliquot of this test solution. Continue the procedure in accordance with IS0 10349-6:199
36、2, clause 4, using 5 ml of the halide standard solution A. 7.5 pH value 7.51 Specification The pH of the solution shall be between 5,3 and 8,7. 7.5.2 Apparatus 752.1 Electronic pH-meter, equipped with a glass electrode and standard reference electrode. 4 0 IS0 IS0 3626: 1996(E) 7.5.3 Procedure Weigh
37、, to the nearest 0,l g, a test portion of about 5 g and dissolve it in about 80 ml of boiled water. Dilute to 100 ml. Measure the pH of the solution at 20 OC, using the pH-meter (7.5.2.1) in accordance with the manufacturers instructions. 7.6 Sulfur compounds For use in non-developer solutions (e.g.
38、 fixers), the less-sensitive iodine consumption test is adequate, whereas for use in developers the more-sensitive ammoniacal silver nitrate test is required. 7.6.1 Amount precipitated by ammoniacal silver nitrate 4) 7.6.1.1 Specification Maximum content of sulfur shall be 0,001 % (m/m). 7.6.1.2 Rea
39、gents 7.6.1.2.1 Sulfide standard solution (1 ml = 0,010 mg S2-). Dissolve I ,5 g of sodium sulfide nonahydrate (Na2SSH20) (DANGER: (B)(S) in 100 ml of water in a 200 ml volumetric flask. Dilute to volume with water and mix well. Pipette 1 ml of this solution into a 100 ml volumetric flask, dilute to
40、 volume with water and mix well. Label this solution “sulfide standard”. 7.6.1.2.2 Ammonium hydroxide (NHdOH), p = 0,91 g/ml (DANGER: (C)(B). 7.6.1.2.3 Silver nitrate (AgNOz), 100 g/l solution 3). 7.6.1.2.4 Silver nitrate, standard volumetric solution of 0,001 mol/l (0,170 g/l) 2) 3). 7.6.1.3 Appara
41、tus 7.6.1.3.1 Two matched Nessler colour-comparison cylinders, of 50 ml capacity. 7.6.1.4 Procedure Weigh, to the nearest 0,Ol g, a test portion of about 1 g and dissolve it in 25 ml of water. Add this solution to a mixture of 20 ml of ammonium hydroxide (7.6.1.2.2) (DANGER: (C)(B) and 2 ml of the s
42、ilver nitrate (7.6.1.2.3). Also prepare a control by adding 1 ml of sulfide standard (7.6.1.2.1) to a mixture of 20 ml of water, 20 ml of ammonium hydroxide (7.6.1.2.2) and 3 ml of 0,001 mol/l silver nitrate (7.6.1.2.4). Heat both solutions in a boiling water bath for 15 min. Cool, transfer to the N
43、essler colour-comparison cylinders (7.6.1.3.1) and dilute to 50 ml. Corn pare the col ours produced in the two N ess ler col our-corn shall not exceed that produced in the sulfide sta ndard control. parison cylinders. Any colour produced in the sample CAUTION - Dispose of all test solutions and rins
44、e all used apparatus immediately. Explosive compounds may be formed on standing. 4) The test method given here for sulfur compounds is not the same as the ammoniacal silver nitrate test given in IS0 10349-g: 1992, Photography - Photographic-grade chemicak - Test methods - Part 9: Reaction to ammonia
45、cal silver nitrate. 5 IS0 3626: 1996(E) 7.6.2 Iodine consumption 7.6.2.1 Specification To pass test. 7.6.2.2 Reagents 7.6.2.2.1 Iodine (12), standard volumetric solution of 0,100 mol/l 2). 7.6.2.2.2 Sulfuric acid (H2SO4), 10 % solution 5). 7.6.2.2.3 Salicylic acid (HOCGHCOH), 1 % (IO g/l) solution.
46、Prepare a solution of 1 g of salicylic acid in 100 ml of water. 7.6.2.2.4 Starch indicator, 5 g/I solution. Stir 5 g of soluble starch with 100 ml of salicylic acid (7.6.2.2.3). Then add 300 ml to 400 ml of boiling water and boil until the starch dissolves. Finally, dilute to 1 000 ml with water. 7.
47、6.2.3 Procedure Dissolve 4,95 g to 5,05 g of the sample in 50 ml of water. Add I,7 ml of the sulfuric acid (7.6.2.2.2), 1 g of potassium iodide (KI) and 1 ml of starch indicator (7.6.2.2.4). Titrate with the iodine solution (7.6.2.2.1). Not more than .I ,O ml of the iodine solution shall be required
48、. 7.7 Sulfate content (as SO423 7.7.1 Specification Maximum content of sulfate shall be 0,06 % 7.7.2 Reagents (m/m) O,l % (m/m) as K2SO4l. 7.7.2.1 Hydrochloric acid (HCI), (1 + 9) solution 6). 7.7.2.2 Barium chloride Dissolve 100 g of barium chloride dihydrate (BaCl2.2H20) (DANGER: (S) in 1 000 ml o
49、f water. 7.7.2.3 Sulfate standard solution (I ml = 0,lO mg S&2-). Dissolve a soluble sulfate salt in water e.g. 181 mg of potassium sulfate (K2SO4) in 1 000 ml of water. 7.7.3 Apparatus 7.7.3.1 Two matched Nessler colour-comparison cylinders, of 50 ml capacity. 5) This solution may be prepared from concentrated sulfuric acid, p = I,8 g/ml (DANGER: (C). 6) This solution may be prepared from concentrated hydrochloric acid, p = 1 ,I 8 g/ml (DANGER: (C)(B). 6
