Development of a method for the determination of UV filters in water samples using stir bar sorptive extraction and thermal desorption–gas chromatography–mass spectrometry

Abstract: Stir bar sorptive extraction (SBSE) in combination with thermal desorption–gas chromatography–mass spectrometry (TD–GC–MS) was applied for the determination of 9 UV filters in water samples. The stir bar coated with polydimethylsiloxane (PDMS) was added to 20mL of water sample at pH 2 (10% MeOH) and stirred at 1000rpm for 180min. Then, the stir bar was subjected to TD–GC–MS. The desorption conditions (desorption temperature and desorption time) and SBSE parameters (ionic strength, pH, presence of organic solvent and time) were optimised using a full factorial design and a Box-Behnken design, respectively. The method shows good linearity (correlation coefficients >0.994) and reproducibility (RSD<16%). The extraction efficiencies were above 63% for all the compounds. Detection limits were between 0.2 and 63ng/L. The developed method offers the ability to detect several UV filters at ultra-low concentration levels with only 20mL of sample volume. The effectiveness of the method was tested by analysing real samples such as lake water, river water and treated wastewater. The application of the method allowed reporting the levels of UV filters in environmental water samples. [Copyright &y& Elsevier]