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In the present study, a novel and efficient adsorbent constructed of molecularly imprinted polymer on the surface of modified magnetic nanoparticles with oleic acid (MNPs) was applied for the selective extraction of ezetimibe. The magnetic molecularly imprinted polymer (MMIP) was polymerized at the surface of modified MNPs using methacrylic acid as functional monomer, ezetimibe as template and ethylene glycol dimethacrylate as cross-linker. The resulting MMIP showed high adsorption capacity, good selectivity and fast kinetic binding for the template molecule. It was characterized by Fourier transform infrared analysis, scanning electron microscopy and transmission electron microscopy methods. The maximum adsorption capacity of MMIP was obtained as 137.1 mg g −1 and it took about 20 min to achieve the equilibrium state. The adsorption model of the adsorbent was fitted with the Freundlich and Langmuir isotherm equations. The assay exhibited a linear range of 0.003-20.000 mg L −1 for ezetimibe with a correlation coefficient of 0.995. The relative standard deviations for the recoveries were <5.2. The method was also examined for the analysis of ezetimibe in the biological samples.

A comparison between C(18) silica and multi-walled carbon nanotubes (MWCNTs) in the extraction of Chlorpyrifos and Phosalone in environmental water samples was carried out using HPLC. Parameters affecting the extraction were type and volume of elution solvent, pH and flow rate of sample through the adsorbent. The optimum conditions obtained by C(18) cartridge for adsorption of these pesticides were 4 mL dichloromethane as elution solvent, sample pH of 5, flow rate of 1 mL/min, and those for MWCNT cartridge were 3 mL dichloromethane, pH of 5 and flow rate of 10 mL/min, respectively. Optimized mobile phase for separation and determination of these compounds by HPLC was methanol/water (80:20 v/v) with pH=5 (adjusted with phosphate buffer). Under optimal chromatographic and SPE conditions, LOD, linear range and precision (RSD n=8) were 3.03x10(-3), 0.01-5.00 microg/mL and 2.7% for Chlorpyrifos and 4.03x10(-4), 0.01-5.00 microg/mL and 2.3% for Phosalone, in C(18) cartridge, respectively. These values for MWCNT were 4.02x10(-6), 0.001-0.500 microg/mL and 1.8% for Chlorpyrifos and 1.02x10(-6), 0.001-0.500 microg/mL and 1.5% for Phosalone, respectively.

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The aim of this work was to develop a method for the clean-up and preconcentration of warfarin from biological sample employing a new molecularly imprinted polymer (MIP) as a selective adsorbent for solid-phase extraction (SPE). This MIP was synthesized using warfarin as a template, pyrrole as a functional monomer and vinyl triethoxysilane as a cross-linker. The molar ratio of 1:4:20 (template-functional monomer-cross-linker) showed the best results. Nonimprinted polymers (NIPs) were prepared and treated with the same method, but in the absence of warfarin. The prepared polymer was characterized by Fourier transmission infrared spectrometry and scanning electron microscopy. An adsorption process (SPE) for the removal of warfarin using the fabricated MIPs and NIPs was evaluated under various conditions. Effective parameters on warfarin extraction, for example, type and volume of elution solvent, pH of sample solution, breakthrough volume and maximum loading capacity, were studied. The limits of detection were in the range of 0.0035-0.0050 µg mL(-1). Linearity of the method was determined in the range of 0.0165-10.0000 µg mL(-1) for plasma and 0.0115-10.0000 µg mL(-1) for urine with coefficients of determination (R(2)) ranging from 0.9975 to 0.9985. The recoveries for plasma and urine samples were >95%.