Detection of phthalate esters in seawater by stir bar sorptive extraction and gas chromatography-mass spectrometry

We developed the stir bar sorptive extraction (SBSE)-gas chromatography-mass spectrometry (GC-MS) method to detect 15 kinds of PAEs in seawater. The stir bars (20 mm in length and 1 mm in film thickness) coated with 150 μL of polydimethylsiloxane (PDMS) were found to demonstrate the optimal extraction of PAEs. The optimal conditions were as follows: extraction time of 2 h, extraction temperature of 25 °C, sodium chloride of 5%, methanol of 10%, analytical time of 50 min, and methanol-acetonitrile (4:1) as the solvent. SBSE-GC-MS revealed that under the set temperature, the chromatographic peaks of all 15 PAEs can appear with complete separation. The detection limit ranged from 0.07 μg/L to 5.71 μg/L, whereas the limit of quantification ranged from 0.023 μg/L to 193 μg/L, and the correlation coefficients between the chromatographic peak area and concentration of the PAEs were greater than 0.92.