DETERMINATION OF NONYLPHENOL AND OCTYLPHENOL ETHOXYLATES IN EFFLUENT BY LIQUID-CHROMATOGRAPHY WITH FLUORESCENCE DETECTION

A robust liquid chromatographic (LC) method with fluorescence detectio n is described for the simultaneous determination of the nonionic surf actants nonylphenol ethoxylates (NPEO) and octylphenol ethoxylates (OP EO) in effluent samples from sewerage treatment plants. The cleanup pr ocedure uses graphitized carbon black solid-phase extraction cartridge s. A subsequent derivatization step removes matrix interferences that are no longer fluorescent after acetylation. The efficiency of the met hod is monitored by inclusion of a surrogate compound designed and syn thesized specifically for this purpose. The limit of reporting for the method is 5 mu g/L for 100 mL effluent samples. Studies on confirmati on of identity of NPEO and OPEO by electrospray LC/mass spectrometry a re described.