Determination of tetrabromobisphenol-A, tetrachlorobisphenol-A and bisphenol-A in soil by ultrasonic assisted extraction and gas chromatography-mass spectrometry

In this work, an isotope dilution method for the determination, in agricultural and industrial soil samples, of tetrabromobisphenol-A, tetrachlorobisphenol-A and bisphenol-A by gas chromatography-mass spectrometry was developed. The compounds were extracted from soil by sonication assisted extraction in small columns (SAESC) with a low volume of ethyl acetate as extraction solvent. For dirty soil samples, such as industrial soils, a simultaneous clean-up on an acidified Florisil-anhydrous sodium sulfate mixture was carried out to remove interferences. After extraction, solvent was evaporated and analytes were derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and determined by isotope dilution gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode (GC-MS-SIM), using C-13(12) labeled compounds as internal standards. Recoveries from spiked samples were between 88% and 108% and the estimated limits of detection (S/N = 3) varied from 30 pg(-1) to 90 pg g(-1). The response obtained with this method was linear over the range assayed, 5-300 ng ml(-1), with correlation coefficients equal or higher than 0.999. The validated method was used to investigate the levels of these phenolic compounds in soil samples collected from different locations in Spain. Bisphenol-A was detected in all samples at concentrations from 0.7 ng g(-1) to 4.6 ng g(-1) in agricultural soils and from 1.1 ng g(-1) to 44.5 ng g(-1) in industrial Soils. Tetrabromobisphenol-A was found in various Soil samples at levels in the range of 3.4-32.2 ng g(-1) ill industrial soils and at 0.3 ng g(-1) in one agricultural soil, whereas tetrachlorobisphenol-A was not detected. (C) 2009 Elsevier B.V. All rights reserved.