Magnetic solid phase extraction with carbon-coated Fe3O4 nanoparticles coupled to HPLC-UV for the simultaneous determination of losartan, carvedilol, and amlodipine besylate in plasma samples.

In this paper, a chemical coprecipitation method was used for the synthesis of Fe3O4 magnetic nanoparticles. The Fe3O4 magnetic nanoparticles were then modified by carbon via a simple hydrothermal method by using glucose. The synthesized Fe3O4 and carbon-coated Fe3O4 (C/Fe3O4) magnetic nanoparticles were characterized by diverse techniques such as XRD, FESEM, EDX, FTIR, and BET. The characterization results were confirmed the formation of the uniformly magnetic nanoparticles and a successful modification of them by carbon. The FTIR spectra confirmed the presence of functional groups on the C/Fe3O4 magnetic nanoparticles surface. The magnetic nanoparticles were used for extraction of losartan, carvedilol, and amlodipine besylate from plasma samples based on magnetic solid phase extraction (MSPE) technique. The effective parameters on extraction efficiency were optimized by multivariate optimization. Under the optimized experimental conditions the MSPE method showed wide linear ranges (1-7500 ng mL-1), low detection limits (0.09-0.69 ng mL-1), good extraction recoveries (56.35-66.43%), and low RSD values (1.6-5.8%). Despite high protein binding of the drugs, the analyses of them were done without protein precipitation. The accuracy was studied by analyses of the spiked plasma samples at different concentrations.