Development of a solid-phase microextraction method for the determination of short-ethoxy-chain nonylphenols and their brominated analogs in raw and treated water

Abstract

A direct solid-phase microextraction (SPME) procedure has been developed and applied for the simultaneous determination of nonylphenol, nonylphenol mono- and diethoxylates and their brominated derivatives in raw and treated water at low μg l −1 concentrations. Several parameters affecting the SPME procedure, such as extraction mode (headspace or direct-SPME), selection of the SPME coating, extraction time, addition of organic modifiers such as methanol and temperature were optimized. The divinylbenzene–carboxen–polydimethylsiloxane fiber was the most appropriate one for the determination of nonylphenol ethoxylates (NPEOs) and bromononylphenol ethoxylates (BrNPEOs) by SPME–GC–MS. The optimized method was linear over the range studied (0.11–2.5 μg l −1) and showed good precision, with RSD values between 4 and 15% and detection limits ranging from 30 to 150 ng l −1 depending on the compound. The SPME procedure was compared with a solid-phase extraction–GC–MS method (C 18 cartridge) for the analysis of NPEO and BrNPEOs in water samples. There was good agreement between the results from both methods but the SPME procedure showed some advantages such as lower detection limits, a shorter analysis time and the avoidance of organic solvents. The optimized SPME method was applied to determine nonylphenol and brominated metabolites in raw and treated water of Barcelona (NE Spain).