Synthesis of Magnetic Halloysite Nanotube-Based Molecularly Imprinted Polymers for Sensitive Spectrophotometric Detection of Metoclopramide in Urine Samples

Abstract

A novel molecularly imprinted polymer was synthesized on magnetic halloysite nanotube via surface initiated reversible addition-fragmentation chain transfer polymerization in the presence of 2-aminoethylmethacrylamide, 2-Cyano-2-propyl benzodithioate, ethylene glycol dimethacrylate (EGDMA) and azobis(isobutyronitrile) for sensitive and selective spectrophotometric determination of metoclopramide in urine samples. The synthesized imprinted polymer was characterized by several surface characterization techniques and the results indicated there was a thin polymer network on the magnetic halloysite nanotube. The rebinding properties of the molecularly imprinted magnetic halloysite nanotube were also investigated in detail and the maximum adsorption capacity and imprinting factor were found to be 37.8 mg/g and 4.51, respectively. The application of the proposed method was carried out by enrichment and spectrophotometric determination of metoclopramide via formation of a charge transfer complex between picric acid and eluted metoclopramide. Under the optimized conditions, the calibration curve was linear in the concentration range of 5.0-150.0 ng/mL and the limit of detection and the limit of quantification were calculated to be 1.5 ng/mL and 4.95 ng/mL, respectively. The inter-day and intra-day precisions were below 5% and recoveries were between 92.8% and 99.2%. The results showed that the proposed method increased the sensitivity and selectivity for spectrophotometric determination of metoclopramide.