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.