Extraction and determination of polyoxyethylene alkyl ether non-ionic surfactants in water at trace levels

Abstract

Polyoxyethylene non-ionic surfactants of the type RO(CH₂CH₂O)_{text-decoration:overlinen}H (where R is an n-alkyl group and text-decoration:overlinen is the number-average degree of polymerisation) are extracted and concentrated from water at trace levels with 1,2-dichloroethane and then determined by a spectrophotometric procedure. Their characteristic polydispersity is checked by gas chromatography. The proposed method, which has been studied in detail on polyoxyethylene dodecyl ethers, is free from interferences from anionic surfactants and the interference of cationic surfactants is also reduced about 15-fold. The determination of non-ionic surfactants in polluted sea waters is considered as a tentative application to a complex matrix.