Molecularly imprinted polymers coated on carbon nanotubes for matrix solid phase dispersion extraction of camptothecin from Camptotheca acuminate

Abstract

A molecularly imprinted polymer (MIP)-matrix solid phase dispersion (MSPD) method for the extraction of camptothecin from Camptotheca acuminate was developed. MIPs were synthesized by a surface imprinting technique using carbon nanotubes as a support, camptothecin as a template, methacrylic acid as a functional monomer, and ethylene glycol dimethacrylate as a crosslinker. The MIPs were characterized by scanning electron microscopy, transmission electron microscopy and Fourier transform-infrared spectroscopy. Isothermal adsorption, dynamic adsorption and selectivity adsorption experiments were also carried out in this study. The MIP-MSPD method coupled with high performance liquid chromatography was applied for the determination of camptothecin in Camptotheca acuminate fruit, bark and leaf. Factors affecting the extraction yield such as the sorbent/sample ratio, dispersion time, and washing and elution solvents were investigated. Under optimized conditions, a good linearity of camptothecin was obtained in a range of 1–200 μg mL⁻¹, and the detection limit of the method was 0.13 μg mL⁻¹. The extraction yields of camptothecin obtained were 0.1055%, 0.0628% and 0.0930% for Camptotheca acuminate fruit, bark and leaf, respectively. The recovery of camptothecin was in the range of 96.1–103.3%. The results showed that this method is fast, selective, cost-effective and environmentally friendly compared with other extraction methods such as stirring extraction, ultrasonic extraction and Soxhlet extraction used for the extraction of camptothecin.