Determination of nonionic detergents surfactants

In the procedure described, Dragendorff s reagent, potassium iodide bismuthate KBil i , forms a deeply orange-red-coloured adduct with many nonionic detergents (surfactants) from aqueous solutions. The adduct is filtered off and dissolved, and the bismuth contained in the adduct is determined by potentiometric titration or by AAS or ICP. 

The following types of nonionic detergents can be determined with the aid of this method  

Oxalkylated fatty acids, fatty alcohols, fatty amines, alkylphenols and 

The content of nonionic detergents (surfactants) is ideally measured 

Low-molecular alkylene glycols such as tetra-, tri- and di-alkylene glycol are no longer capable of precipitation. Protein and its breakdown products including the amino acids and other surface-active agents with cationic or anionic reactivity do not give a positive reaction unless ethylene oxide groups are present in the molecule. 

---