Parts per trillion level determination of endocrine-disrupting chlorinated compounds in river water and wastewater effluent by stir-bar-sorptive extraction followed by gas chromatography–triple quadrupole mass spectrometry

Abstract

A new analytical method using stir-bar-sorptive extraction (SBSE) followed by liquid desorption (LD) and gas chromatography with triple-quadrupole mass spectrometric detection (GC-QqQ-MS-MS) has been used for quantitative determination of 25 chlorinated endocrine-disrupting compounds (EDCs) in river water and wastewater. The experimental conditions affecting the SBSE-LD performance were studied and are discussed in detail. Results from systematic assay revealed that a 100-mL water sample, stir bars coated with 47 μL PDMS, an extraction time of 14 h (at 900 rpm), 5 % MeOH as modifier and 10 % NaCl resulted in the best analytical recovery of all the target compounds studied. Use of 1:1 ACN-MeOH as back-extraction solvent and two successive sonication steps, each for 5 min, resulted in the best performance for monitoring EDCs in water matrices. The method detection limits for most of the target compounds were very good- ≤ 2 ng L(-1) and ≤10 ng L(-1) for river water and wastewater effluents respectively. Experimental recovery for all the compounds was >70 %, with the exception of simazine for which recovery from the matrix was 65 %. Signal enhancement observed for a few of the compounds in wastewater effluents was managed by use of matrix-matched standards and different injection liners. The method was successfully used for analysis of river water samples from Henares River (Spain) and wastewater effluent samples from wastewater-treatment plants (WWTP). Eleven of the 25 compounds studied were detected in both river water and wastewater effluents. Terbutylazine and methoxychlor were detected in almost all the river water and effluent samples; amounts varied between 37-58.5 ng L(-1) and 15.2-46.8 ng L(-1), respectively. This method was shown enable reliable, effective, and sensitive monitoring of chlorinated EDCs at nanogram levels in surface water and wastewater effluent.