High-performance liquid chromatography-fluorescence determination of aliphatic alcohol polyethoxylates and poly(ethylenglycol)s in aqueous samples

New derivatization and separation procedures for the routine determination of detergent alcohol polyethoxylates (AEs) and poly(ethylene glycol)s (PEGs) in aqueous environmental and biodegradation screening test samples are proposed. The AE derivatives were separated both homolog-by-homolog or ethoxymer-by-ethoxymer by reversed-phase HPLC-fluorescence (RP-HPLC-FL) after derivatization with naphthyl isocyanate (NIC) and naphthoyl chloride (NC), respectively. The ethoxymer-by-ethoxymer separation of PEGs was obtained by RP-HPLC-FL after derivatization with NC. The fluorescence response of the various AE homologs and AE, PEG ethoxymers were evaluated. AE, PEG as well as nonylphenol polyethoxylates were cumulatively extracted from biodegradation test liquors and sewage-treatment plant influent and final effluent samples by solid-phase extraction on graphitized carbon black (GCB), and then derivatized and analyzed by RP-HPLC-FL. The recovery was systematically >90%, with relative standard deviations of 3-6%, for all compounds considered. The proposed derivatization, separation and detection procedures showed a sensitivity of 5-10 ng of injected AE or PEG derivatives leading to a S/N ratio of 10.