Synthesis of magnetic nanoparticle‐based molecularly imprinted polymer as a selective sorbent for efficient extraction of ezetimibe from biological samples

Abstract

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.

Sample Preparation Using Molecularly Imprinted Polymers

“…94 In most of the cases, 5-100 mg of particles are dispersed in the samples. The ratio between the amount of MIP particles and the volume of the sample, that has only been optimized in some cases, 68,180 can be lower than 1, 32,33,44,94,143,158,169,179 between 1 and 10, 45,50,58,59,61,64,65,89,98,106,107,111,114,117,147,154,155,[163][164][165]170,177,178,185 or up to 50 34,66,69,144,149,168,174,181,188 and even 250 mg/mL. 43 Environmental waters were filtered 172 or directly put in contact with the MIP particles for the extraction of target analytes.…”

“…144 Wine samples were first treated by LLE to remove some interfering compounds. 154 Urine samples were extracted without any treatment, 113,164,173 or after pH adjustment, 165 filtration, 174 centrifugation, 147 dilution by a factor of 25, 153 or a complex sample pretreatment involving a dilution with a buffer (1:1, v/v) and a first SPE extraction step on C18 silica. 149 For serum samples, a direct extraction, 173 a dilution by a factor 50, 111 100, 105,106 150, 114 200 118 or 250, 66 or a protein precipitation step 69 that can be followed by a dilution with a buffer was proposed.…”

“…Some authors also reported the use of ultrasound to shorten the dSPE duration time. 147,155,156,165,174 The optimization of the extraction conditions with real samples is very rarely described. In most of the cases, it is worthwhile to notice that the optimization was achieved by studying the binding of the target molecule(s) in pure media, in very few cases with also a comparison with the NIP, and then the optimal conditions were applied for real samples without any additional study of matrix effects.…”

“…32 As with conventional dSPE sorbents, the key-parameters to be optimized are the sample volume, the ratio of the sample volume and the amount of sorbent, the extraction time, the agitation rate, the pH of the sample, the nature of the solvent, and the time required for desorption. 189 In MIP-dSPE, a washing step was in some cases introduced before desorption to remove some interfering compounds, 50,62,162,164,165,170,173 but no real optimization of this step was reported. Some other parameters can also be studied such as the number of extraction or desorption steps or the use of shaking devices (rotary shaker, ultrasonic bath).…”

“…155 As for SPE-MIP, the validation of a dSPE procedure was mainly based on the intra-and interday studies of the extraction recoveries, measured mainly in pure media 59,96,180,184 but also in real samples, in their native form 62,181 or spiked at different concentration levels. 37,45,50,51,62,65,69,94,96,113,149,163,165,168,172,174,178,183,184 Li et al compared MIP and C18 silica particles to evaluate their difference in term of adsorption capacity of drugs from environmental waters, that was higher with the MIP (factor 2.6). 155 A similar comparison was reported by Lu et al that observed a higher selectivity, with a better clean-up effect with the MIP.…”