# ISO 994:1973 — Withdrawn and superseded ISO standards

For ISO 994:1973, item title is Potassium hydroxide for industrial use — Determination of iron content — 1,10- Phenanthroline photometric method; status code is 9599; successor is ISO/CD 994; withdrawn / published date is 1973-04-01, recorded from its source on 2026-08-05.

- **Identifier:** ISO 994:1973 _(verified: appears in the quote below)_
- **Item title:** Potassium hydroxide for industrial use — Determination of iron content — 1,10- Phenanthroline photometric method _(verified: appears in the quote below)_
- **Status code:** 9599 _(verified: appears in the quote below)_
- **Successor:** ISO/CD 994
- **Withdrawn / published date:** 1973-04-01 _(verified: appears in the quote below)_

## What the source says

> 5437,IS,,ISO 994:1973,"Potassium hydroxide for industrial use — Determination of iron content — 1,10- Phenanthroline photometric method","Hydroxyde de potassium à usage industriel — Dosage du fer — Méthode photométrique à la 1,10- phénanthroline",1973-04-01,1,['71.060.40'],ISO/TC 47,9599,,[5438],"['en','fr']",2,"<p>Describes a method that is more sensitive and more widely used than the 2,2'-bipyridyl method. It is applicable to products having iron contents equal to or greater than 0.3 mg/kg. The principle is based on the reduction of iron(III) by hydroxylammonium chloride, formation of a iron(II)/1,10-phenanthroline complex in a buffered system. Photometric measurement of the coloured compl

## Source

- https://isopublicstorageprod.blob.core.windows.net/opendata/_latest/iso_deliverables_metadata/csv/iso_deliverables_metadata.csv

Last verified: 2026-08-05. Review by: 2027-02-01.
Part of [Withdrawn and superseded ISO standards](https://referencesource.org/iso-standard-supersessions/).