A composite of magnetic GOx@MOF incorporated in alginate hydrogel fiber adsorbent for the extraction of phthalate esters

A composite alginate hydrogel magnetic fiber adsorbent was developed for the extraction and enrichment of phthalate esters. The adsorbent was fabricated by integrating graphene oxide (GOx), a metal organic framework (MOF) and magnetite nanoparticles (Fe3O4) into alginate hydrogel fiber. The developed composite hydrogel fiber adsorbent was characterized. The fabrication procedure and extraction condition included the amount of GOx and MOF in the composite fiber, the dosage of composite hydrogel fiber adsorbent, the extraction time, desorption condition, sample volume, stirring rate and sample pH were optimized. The composite hydrogel fiber adsorbent was used for the extraction and coupled with high performance liquid chromatography for the separation, identification and determination of phthalate esters in water, juice and tea. Applied composite adsorbent for the extraction of phthalate esters and quantitative analysis with HPLC technique provided good linearity in the ranges of 3.0–250.0 μg L−1 for benzyl butyl phthalate and dibutyl phthalate, and 5.0–250.0 μg L−1 for bis(2-ethylhexyl) phthalate and di-n-octyl phthalate. The coefficients of determination were >0.998. The limits of detection and limits of quantification were achieved in the range of 3.0–5.0 μg L−1 and 10.0–15.0 μg L−1, respectively. The developed method was successfully applied to determine phthalate esters in water, juice and tea with satisfactory recoveries from 80.7 to 89.9 % with RSDs lower than 8 %. The developed composite alginate hydrogel fiber adsorbent showed good accuracy, precision, and reproducibility and could be reused 16 times. The extraction procedure was simple and convenient.