Zn (II)-imidazole derived metal azolate framework as an effective adsorbent for double coated solid-phase microextraction of sixteen polycyclic aromatic hydrocarbons

Zn (II)-imidazole derived metal azolate framework materials were synthesized via rapid solvent reaction and developed as an effective adsorbent for solid-phase microextraction of trace sixteen polycyclic aromatic hydrocarbons (PAHs) from real samples prior to their determination by HPLC. The adsorbent was characterized by Fourier transform infrared spectrometry, X-ray diffractometry, Scanning electron microscopy, Thermal gravimetric analysis and Nitrogen adsorption-desorption. An orthogonal array design (OAD) was carried out to evaluate the variables affecting extraction efficiency. Under the optimum conditions, the proposed method showed low limits of detection (LOD, 0.006-0.54 mu g L-1), wide linear ranges (0.02-2000 mu g L-1), and good repeatability (the relative standard deviation (RSD) is 0.11%-4.93% for single fiber and 0.42%-7.36% for fiber-to-fiber). The spiked recoveries at two levels of 20.0, 50.0 mu g L-1 were in the range of 76.5%-112.0% with the RSDs less than 8.3%. Compared with commercial fibers and other reported methods, the homemade fiber displayed excellent extraction capacity. The MAF-6 coating was stable over 120 successive cycles of extraction/desorption without significant loss of extraction efficiency. The method was successfully applied for the determination of sixteen PAHs in real samples.