Occurrence of Fluorescent Whitening Agents in Sewage and River Water Determined by Solid-Phase Extraction and High-Performance Liquid Chromatography

Abstract

Fluorescent whitening agents (FWAs) used in laundry detergents were determined in aqueous samples from sewage treatment plants and rivers using solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) with post-column UV irradiation and fluorescence detection. FWAs were extracted from 10−200-mL water samples with C18 bonded- phase silica extraction disks and eluted with methanol-containing tetrabutylammonium ion-pairing reagent. No further sample cleanup steps were necessary due to the sensitive and selective fluorescence detection. Recovery of FWAs from raw sewage, primary effluent, secondary effluent, and river water ranged from 76 to 96%. The overall precision of the method, indicated by the relative standard deviation, ranged from 1 to 11%. The limit of quantification was less than 30 ng/L. The concentrations of the two most frequently used FWAs ranged from 7 to 21 μg/L in primary effluent, from 2.6 to 8.9 μg/L in secondary effluent, and from 0.04 to 0.57 μg/L in river water. FWA...