Separation and determination of oligomers and homologues of aliphatic alcohol ethoxylates in textile lubricants and lubricant emulsion by high-performance liquid chromatography

Homologous mixtures of 3,5-dinitrobenzenoates of aliphatic alcohol ethoxylates (AEs) were separated by high-performance liquid chromatography (HPLC) with high resolution using an amino bonded silica column and gradient elution of ternary solvents (hexane-dichloromethane-methanol). When the method was combined with novel sample clean-up and extraction procedures, oligomers of AEs in textile lubricants and a lubricant emulsion were satisfactorily determined with recoveries >75% and good reproducibility. A reversed-phase HPLC method was also developed to characterise the alkyl groups of AEs.