This standard specifies the two-phase titration procedure for the determination of anionic-active matter present in anionic surface active agents and detergents.
The manual method is applicable to the determination of alkylbenzene sulfonates; alkane sulfonates, sulfates and hydroxysulfates; alkylphenol sulfates; fatty alcohol methoxy- and ethoxysulfates; dialkylsulfosuccinates and other solids or to aqueous solutions of the active material containing one hydrophilic group per molecule.
The method is not applicable if cationic surface active agents are present.
If the analysis result is expressed in mass percentage, the relative molecular mass of the anionic active matter has to be known.
Note:
① Low relative molecular mass sulfonates present as hydrotropes (toluene, xylene) do not interfere when present in concentrations of up to 15% (m/m) relative to the active matter. At higher levels, their influence should be evaluated in each particular case.
② Soap, urea and salts of (ethylenedinitrilo) tetraacetic acid do not interfere.
③ In the presence of non-ionic surface agents, their influence should be evaluated in each particular case.
④ Typical inorganic components of detergent formulations, such as sodium chloride, sulfates, borates, tripolyphosphates, perborates, silicates, etc., do not interfere, but bleaching agents other than perborate should be destroyed before the analysis, and the sample should be completely soluble in water.
2 Normative references
GB/T 13173.1 Method of sample division for detergents
3 Principle
Determination of the anionic-active matter in a medium consisting of an aqueous and a chloroform phase by titration with a standard volumetric cationic-active solution (benzethonium chloride) in the presence of an indicator which consists of a mixture of a cationic dye (dimidium bromide) and an anionic dye (acid blue 1).
