Determination of chlorophenols in water by liquid chromatography method after magnetic solid phase extraction based on SiO2/MIL-101@Fe3O4 nanoadsorbent

Liquid chromatographic determination of chlorophenols in water and wastewater samples was performed following magnetic solid phase extraction based on SiO2/MIL (Materials Institute Lavoisier)-101@Fe3O4 nanoadsorbent. To the best of our knowledge, there is no report on the synthesis and application of SiO2/MIL-101@Fe3O4 for enrichment and extraction of chlorophenols. The nanoadsorbent was characterized by scanning electron microscopy, transmission electron microscopy, Fourier Transform infrared spectroscopy, and vibrating sample magnetometry. One variable at a time and central composite design were used for optimization. The optimum conditions were achieved as following: pH value, 4.7; sample volume, 40 mL; nanoadsorbent amount, 25.0 mg; adsorption time, 3.5 min sonication; salt concentration, 10% w/v NaCl; eluent volume, 140 mu L 0.01 mol/L HCl in methanol. After optimization, linearity was attained in the range of 0.2-300 mu g L-1 (r(2) > 0.9978) and limits of detection were 0.06-0.2 mu g L-1. Method precision as relative standard deviation was less than 6.7% and enrichment factors were achieved in the range of 134-189. The proposed method based on using SiO2/MIL-101@Fe3O4 nanoadsorbent is simple and fast owing to the magnetically-assisted separation. Finally, the method was employed for the analysis of mineral water and wastewater samples with satisfactory results (recovery, 89-103%; relative standard deviation, 5.0-7.9%).