Overview
ISO 17531:2002 specifies purity criteria and test methods for the photographic chemical 4-(N-ethyl-N-2-methanesulfonylaminoethyl)-2-methylphenylenediamine sesquisulfate monohydrate (commonly used as a color developer ingredient). The standard defines required assay limits, identity checks, impurity limits and practical laboratory test procedures to ensure material quality for photographic processing applications.
Keywords: ISO 17531:2002, photographic chemicals, sesquisulfate monohydrate, purity specification, assay, quality control.
Key topics and technical requirements
- Scope: Establishes purity criteria for photographic-grade material and specifies test methods to determine purity.
- Physical properties: Appears as white to medium-tan or light-pink granules or powder; relative molecular mass 436.52.
- Hazard & storage: May cause skin irritation/allergic reactions and is corrosive. Handle with care, avoid dust contact, store in tightly sealed containers protected from light at room temperature.
- Mandatory analytical limits (summary):
- Assay: 99.0 % to 102.9 % (by mass)
- Residue after ignition: ≤ 0.10 %
- Heavy metals (as Pb): ≤ 0.002 %
- Iron (Fe): ≤ 0.002 %
- Volatile matter: ≤ 0.60 %
- Appearance of solution: Clear and colourless or pale pink, free from insoluble matter
- Photographic-use test: Must pass defined photographic performance test
- Principal test methods:
- Assay: Potentiometric titration using standard ammonium cerium(IV) hexanitrate (c = 0.0500 mol/L) with ferroin indicator (instructions and formulae provided for result calculation).
- Identity: Infrared (IR) spectrum comparison against reference spectrum.
- Additional tests for residue after ignition, heavy metals, iron and volatile matter referencing ISO 10349 series methods.
Applications and users
- Who uses it: Chemical manufacturers, photographic chemical suppliers, quality control laboratories, photographic film and print processing facilities, and standards bodies.
- Practical value:
- Ensures consistent performance of color developer formulations.
- Prevents photographic defects caused by impurities (staining, fogging, inconsistent color reproduction).
- Provides validated, harmonized test methods for acceptance testing and supplier qualification.
Related standards
Note: ISO 17531:2002 focuses on laboratory test procedures and acceptance limits; safe laboratory practice and appropriate personal protective equipment are recommended when performing the tests.