Analysis of phthalate acid esters in environmental water by magnetic graphene solid phase extraction coupled with gas chromatography–mass spectrometry

In this work, magnetic graphene composites were synthesized via a simple hydrothermal reaction. The as-prepared composites were successfully applied as an effective adsorbent for the preconcentration of seven phthalate acid esters (PAEs) in environmental water samples prior to gas chromatography–mass spectrometry (GC–MS) analysis. The magnetic graphene composites had a unique structure in which magnetite particles were deposited on graphene sheets. This unique structure not only provided strong magnetic responsiveness for the separation but also prevented the self-aggregation of graphene. The magnetic graphene composites had several advantages, such as large surface area, fast separation ability, and high peak intensity for aromatic analytes; these properties are attributed to the distinct structure of magnetic graphene composites, which comprises p-conjugated networks with a highly exposed surface. Various parameters, including eluting solvent and volume, absorbent amount, extraction time and elution time, were optimized. Validation experiments showed that the optimized method presented good linearity (r > 0.997), satisfactory precision (RSD < 8.5%), and high recovery (88–110%). The limits of detection were from 0.010 μg/L to 0.056 μg/L, and the limits of quantification were from 0.035 μg/L to 0.19 μg/L. The proposed method had these advantages of simplicity, good sensitivity, and high efficiency. Finally, the proposed was successfully applied to the analysis of PAEs in real water samples.