CHROMATOGRAPHIC BEHAVIOR OF OLIGOETHYLENE GLYCOL NONYLPHENYL ETHER ANIONIC SURFACTANTS IN NORMAL-PHASE HIGHPERFORMANCE LIQUID-CHROMATOGRAPHY

The retention behaviour of sulphated oligoethylene glycol nonylphenyl ether anionic surfactants was investigated in normal-phase systems wit h nitrile and amino chemically bonded stationary phases and with organ ic mobile phases containing tetraalkylammonium additives. Non-linear p lots of the logarithms of capacity factors versus the number of oxyeth ylene units in sulphated oligomers were observed on the bonded amino c olumn in mobile phases consisting of cetyltrimethylammonium bromide, 2 -propanol and n-heptane. It is possible to separate sulphated oligomer s and their parent non-sulphated analogues in a single run in these sy stems using gradient elution.