ISO 4323:2025

International
Standard
ISO 4323
Third edition
Surface active agents — Soaps —
2025-10
Determination of chloride content
by potentiometric method
Reference number
© ISO 2025
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Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 1
6 Apparatus . 2
7 Sampling . 3
8 Procedure . 3
8.1 Measurement temperature .3
8.2 Standardization of the silver nitrate solution.3
8.2.1 Titration .3
8.2.2 Calculation of solution .4
8.3 Determination .4
8.3.1 Test portion .4
8.3.2 Titration .5
8.3.3 Blank test .5
9 Expression of results . 5
10 Precision . 5
10.1 General .5
10.2 Repeatability .5
10.3 Reproducibility . .5
11 Test report . 5
Annex A (informative) Example V calculation . 7
EQ
Bibliography . 8

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Foreword
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This document was prepared by Technical Committee ISO/TC 91, Surface active agents.
This third edition cancels and replaces the second edition (ISO 4323:2018), which has been technically
revised.
The main changes are as follows:
— Normative references have been revised;
— text revised;
— precision clause added.
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International Standard ISO 4323:2025(en)
Surface active agents — Soaps — Determination of chloride
content by potentiometric method
1 Scope
This document specifies a potentiometric method for the determination of the chloride content in soaps,
with or without other surface-active agents, and also in compounded products.
The method is applicable for chloride mass fractions between 0,01 % to 1,0 %.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 385, Laboratory glassware — Burettes
ISO 648, Laboratory glassware — Single-volume pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 8212, Soaps and detergents — Techniques of sampling during manufacture
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
chloride content
mass fraction of chloride, expressed as sodium chloride and in percent, determined in accordance with the
procedure described in this document
4 Principle
A test portion is dissolved in water and isopropanol. The suspension is acidified with nitric acid then the
chloride ions are titrated potentiometrically with a silver nitrate standard solution by using either a silver
ion selective electrode plus a reference electrode or a combined electrode.
5 Reagents
During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only
distilled water or water of equivalent purity in accordance with ISO 3696.
...