Porous carbon derived from a metal-organic framework as an efficient adsorbent for the solid-phase extraction of phthalate esters

A porous carbon designated as MOF-5-C was prepared by directly carbonizing a metal-organic framework (MOF-5). The morphology and microstructure of MOF-5-C were characterized by scanning electron microscopy, N2 adsorption, and powder X-ray diffraction. The MOF-5-C retained the original porous structures of MOF-5, and showed a high Brunauer-Emmett-Teller surface area (1808 m2 g-1 ) and large pore volume (3.05 cm3 g-1 ). To evaluate its adsorption performance, the MOF-5-C was used as an adsorbent for the solid-phase extraction of four phthalate esters from bottled water, peach juice, and soft drink samples followed by high-performance liquid chromatographic analysis. Several parameters that could affect the extraction efficiencies were investigated. Under the optimum conditions, a good linearity was achieved in the concentration range of 0.1-50.0 ng mL-1 for bottled water sample and 0.2-50.0 ng mL-1 for peach juice and soft drink samples. The limits of detection of the method (S/N = 3) were 0.02 ng mL-1 for bottled water sample, and 0.04-0.05 ng mL-1 for peach juice and soft drink samples. The results indicated that the MOF-5-C exhibited an excellent adsorption capability for trace levels of phthalate esters, and it could be a promising adsorbent for the preconcentration of other organic compounds.