Synthesis of the magnetic composite of Ni-MOF-I in aqueous medium and its application in magnetic dispersive micro solid phase extraction of plasticizers from pharmaceutical samples

For the first time, this research presents the synthesis procedure and analytical application of Ni-MOF-I magnetic composite. The synthesis method was green and done in an aqueous medium. The composite was employed as an adsorbent in a magnetic dispersive solid phase extraction process followed by dispersive liquid-liquid microextraction for the extraction and preconcentration of some plasticizers from pharmaceutical samples stored in plastic containers. The Ni-MOF-I magnetic composite was characterized by applying Fourier transform infrared spectrophotometry, vibrating sample magnetometry, scanning electron microscopy, energy-dispersive X-ray, Xray diffraction, and nitrogen adsorption/desorption analyses. For operating the extraction procedure, initially, the plasticizers were adsorbed onto the adsorbent particles by vortexing. Then, the plasticizers were desorbed from the adsorbent surface using a mL volume of 2-proponal. Subsequently, the obtained eluate phase was mixed with a mixture of 1,2-dibromoethane and 1,1,2-trichloroethane and then injected into deionized water using a glass syringe. Afterward, centrifugation was done to isolate the extractant from the aqueous phase. Eventually, one microliter of the sedimented phase was injected into gas chromatography-flame ionization detection. Acceptable analytical results such as high enrichment factors (355-415) and extraction recoveries (71-83 %), low limits of quantification (0.76-1.08 mu g L-1) and detection (0.23-0.33 mu g L-1), wide linear ranges (1.08-300 mu g L-1), and satisfactory relative standard deviation values of 4.0-6.3 % (intra-day precision, n = 5) and 4.9-7.4 % (inter-day precision, n = 5) were achieved. The suggested procedure was used as a productive analytical method based on the Ni-MOF-I magnetic composite for the extraction and determination of some plasticizers from different pharmaceutical samples filled in plastic containers. Elimination of centrifugation, using 2-propanol as a green desorption/disperser solvent, detection of di-(2-ethylhexyl) phthalate in boric acid alcohol drop, and applying mu L-level of the extraction solvent are the advantages of this proposed method.