Determination of nonylphenol ethoxylate oligomers by liquid chromatography-electrospray mass spectrometry in river water and non-ionic surfactants

Liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) for the quantitative determination of five nonylphenol ethoxylate (NPE) ol igomers in river water was described. These NPE oligomers were separated on a poly(vinyl alcohol) gel column using acetonitrile-30 mM ammonium acetate as the mobile phase followed by ESI-MS detection without any sample concen tration steps. The sample was only filtered using the disposable filter and the aliquot (100 mul) of this sample was injected into the LC-ESI-MS syste m. All NPE oligomers were detected using the [M+NH4](+) ion. Detection limi ts ranged from 160 pg/ml (NPE4) to 240 pg/ml(NPE2), repeatability and repro ducibility ranged from 4.2% (NPE2) to 6.2% (NPE6) and from 7.4% (NPE5) to 9 .8% (NPE6). (C) 2000 Elsevier Science B.V. AU rights reserved.