1、INTERNATIONAL STANDARD Second edition 1994-12-15 Photography - Processing chemicals - Specifications for sodium tetraborate decahydrate Photographie - Produits chimiques de traitement - Spkifications relatives au tktraborate de sodium d V is the volume, in millilitres, of the sodium hydroxide used t
2、o resch the endpoint for the titration (7.1.4); m is the mass, in grams, of the test Portion; 190,7 is the conversion factor obtained from the mass of sodium tetraborate decahydrate equivalent to 1 mole of sodium hydroxide (i.e. 95,35/2; the reaction with mannitol generates 2 equivalents of acid to
3、be titrated with sodium hydroxide per mole of sodium tetraborate) x the conversion factor for milli- litres to litres (i.e. 0,001) x the sampling factor (i.e. 20) x 100 (for percentage). 1) Commercially available analysed reagent is recommended. The solution tan be prepared from sodium hydroxide pel
4、lets, (DANGER: ). (Hazard warning Codes are defined in SS0 10349-1.) 2) The Solution is prepared from concentrated sulfuric acid, p = 1,84 g/ml (DANGER: ). 2 0 ISO ISO 3621:1994(E) 7.2 Heavy metals content (as Pb) 7.2.1 Specification Maximum content of heavy metals shall be 0,002 % (m/m). 7.2.2 Proc
5、edure NOTE 1 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 accord- ante with ISO 10349-5. Use a test Portion of 1,90 g to 2,lO g of the Sample prepared in accordance with ISO 10349-5:1992, 7.2. Use 4 ml of t
6、he heavy metals Standard prepared in accordance with ISO 10349-5: , 8.1.1. 1992, 73 . 7.3.1 Iron content Specification Maximum content of iron shall be 0,003 % (+Iz). 7.3.2 Procedure Determine the percentage of iron in accordance with ISO 10349-5. Use a test Portion of 1,90 g to 2,lO g of the Sample
7、 prepared in accordance with ISO 10349-5: 1992, 7.2. Use 6 ml of the iron Standard prepared in accordance with ISO 10349-5:1992, 8.1 .l . 74 . Reaction to ammoniacal silver nitrate 7.4.1 Specification The material shall pass the test. 7.4.2 Procedure Determine the reaction to ammoniacal silver nitra
8、te in accordance with ISO 10349-9. 7.5 pH value 7.5.1 Specification The pH shall be between 9,14 and 934. 7.5.2 Apparatus Usual laboratory apparatus and, in particular, the following. 7.5.2.1 Electronie pH-meter equipped with a glass electrode and Standard reference electrode. 7.5.3 Procedure Use a
9、Sample of about 100 ml of the 20 g/l Solution - prepared in the assay procedure (7.1.4). 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 Appearance of Solution 7.6.1 Specification The Solution shall be clear and free from i
10、nsoluble matter except for a slight flocculence. 7.6.2 Procedure Inspect the 20 g/l Solution of the Sample prepared in the assay procedure (7.1.4). Observe the Solution for colour and clarity. ISO 3621:1994(E) 0 ISO ICS 37.040.30 Descriptors: photography, photographic materials, photographic chemicals, sodium tetraborate, specifications, matenals specifications, purity criteria, tests, Chemical analysis. Price based on 3 pages
