ANSI IT4.156-2002 pdf download Processing Chemicals – Specifications for Anhydrous Sodium Formaldehyde Bisulfite
1 Scope
This standard establishes criteria for the purity of photographic-grade anhydrous sodium formal- dehyde bisulfite and specifies the tests 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 standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid standards.
ISO 1 0349-1 :1 992, Photography – Photographic-grade chemicals – Test methods – Part 1: General.
ISO 1 0349-3:1 992 (R1 999), Photography – Photographic-grade chemicals – Test methods – Part 3: Determination of matter insoluble in ammonium hydroxide solution.
ISO 1 0349-5:1 992 (R1 999), Photography – Photographic-grade chemicals – Test methods – Part 5: Determination of heavy metals and iron content.
ISO 1 0349-8:1 992, Photography – Photographic-grade chemicals – Test methods – Part 8: Determination of volatile matter.
3 General
3.1 Physical properties
Anhydrous sodium formaldehyde bisulfite, (NaHSO 3 ⋅ HCHO), exists as fine white crystals or a crystalline powder. It has a relative molecular mass of 1 34.09.
3.2 Hazardous properties
Anhydrous sodium formaldehyde bisulfite liberates formaldehyde when treated with strong alkali or when heated. It may also liberate sulfur dioxide and hydrogen sulfide on exposure to strong acids or high temperatures.
3.3 Storage
Anhydrous sodium formaldehyde bisulfite 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 with 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 pro- vide information to the user and are not meant to provide conformance with hazardous labeling requirements, as these vary from country to country.
6 Sampling
See ISO 1 0349-1 .
7 Test methods
7.1 Assay
7.1.1 Specification
The minimum mass fraction of anhydrous sodium formaldehyde bisulfite (NaHSO 3 ⋅ HCHO) shall be 99.0%.