ISO 3627 pdf download

ISO 3627 pdf download.Photography — Processing chemicals — Specifications for anhydrous sodium metabisulfite 1 Scope This International Standard establishes criteria for the purity of photographic-grade anhydrous sodium metabisulfite and specifies the tests to be used to determine the purity. 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 agreements 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 registers of currently valid International Standards. ISO 1 0349-1 :1 992, Photography— Photographic-grade chemicals — Test methods — Part 1: General. ISO 1 0349-5:1 992, Photography — Photographic-grade chemicals — Test methods — Part 5: Determination of heavymetals andiron content. ISO 1 0349-9:1 992, Photography — Photographic-grade chemicals — Test methods — Part 9: Reaction to ammoniacalsilvernitrate. 3 General 3.1 Physical properties Anhydrous sodium metabisulfite (Na 2 S 2 O 5 ) exists as a white or pale-cream granular powder. It has a relative molecular mass of 1 90,1 0. 3.2 Hazardous properties Anhydrous sodium metabisulfite is not hazardous when handled with normal precautions. Avoid contact with acids. 3.3 Storage Anhydrous sodium metabisulfite 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 conform to the requirements specified in ISO 1 0349-1 unless otherwise noted. The hazard warning symbols, used as a reminder in those steps detailing handling operations, are defined in ISO 1 0349-1 . 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 1 0349-1 . 7.1.4.1 Back-titration method Using a pipette (7.1 .3.2), transfer 50,00 ml of the iodine solution (7.1 .2.5) to a glass-stoppered flask. Weigh, to the nearest 0,000 1 g, a test portion of about 0,23 g and wash this into the flask. Add 5 ml of the acetic acid (7.1 .2.2) and mix to ensure complete dissolution of the sample. Using a burette (7.1 .3.1...