Analysis of melamine in milk powder by using a magnetic molecularly imprinted polymer based on carbon nanotubes with ultra high performance liquid chromatography and tandem mass spectrometry

Abstract

A new magnetic molecularly imprinted polymer was coupled with ultra high performance liquid chromatography and tandem mass spectrometry for the selective determination of melamine in milk powder. The magnetic molecularly imprinted polymer has been prepared by using carbon nanotubes as the matrix, Fe O particles as the magnetic ingredient, melamine as the template molecule, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linker and polyvinylpyrrolidone as the dispersant. The polymer was characterized with scanning electron microscopy, Fourier transform infrared spectroscopy and a physical property measurement system. The isothermal adsorption, kinetics adsorption, and selectivity were studied to evaluate the rebinding properties of the magnetic molecularly imprinted polymer. Various parameters affecting the extraction efficiency such as the amount of polymer, extraction time, and eluting solution were evaluated. The limit of detection was 0.00075 mg/kg. The relative standard deviations of the intraday and interday precision are 0.4-2.7 and 2.3-5.1%, respectively. The proposed method was successfully applied to determine melamine in different milk powder samples from different provenances, and satisfactory recoveries of 89.0-95.6% were obtained. This method has great significance for quality control and is simple and suitable for the rapid determination of melamine in milk powder.

Surface-imprinted magnetic nanoparticles for the selective enrichment and fast separation of fluoroquinolones in human serum

“…Compared to traditional bulk‐imprinted strategy, surface imprinting has significant advantages, such as high template removal efficiency, fast mass transfer, controllable and regular shape, and good accessibility to target species . Moreover, MIP materials with superparamagnetic property are superior in easy handing and fast separation from sample matrix since they can be easily isolated by a magnet without retaining magnetism after the removal of the magnet . Fabrication of MIPs on superparamagnetic nanoparticles gives access to smart materials with dual functions of specific molecular recognition and magnetic separation.…”

Extraction of matrine from soil with matrix solid‐phase dispersion by molecularly imprinted polymers derived from lignin‐based Pickering emulsions

“…The peak at 1602 cm −1 is ascribed to the tensile vibration of C=C. The absorption band at 1731 cm −1 correspond to the tensile vibration of C=O from MAA. It indicated that EGDMA and MAA were involved in imprinting polymerization successfully.…”

“…From the FTIR spectra of MIPs (), an intensity peaks at 3445 cm −1 correspond to hydroxyl groups of phenols and aliphatic groups. At 2956 and 1457 cm −1 , there are C–H stretching vibration absorption peaks.…”

“…From the FTIR spectra of MIPs (), an intensity peaks at 3445 cm −1 correspond to hydroxyl groups of phenols and aliphatic groups. At 2956 and 1457 cm −1 , there are C–H stretching vibration absorption peaks. It can be seen that the C–O symmetric and asymmetric tensile vibration bands of ester groups were existing from the peaks at 1260 and 1159 cm −1 , which may be from EGDMA.…”

Efficient synthesis of molecularly imprinted polymers with bio‐recognition sites for the selective separation of bovine hemoglobin

“…The thin imprinted monolayer coated on the surface of a solid support by a surface imprinting process holds a better mass transfer for target template, which is especially important for proteins that are easily enwrapped and difficult to remove completely from the polymer network. Up to now, many materials such as silica nanoparticles , silica nanotubes , alumina membrane , and magnetic nanoparticles have been adopted as the support materials of surface imprinting. Especially, silica nanoparticles are popular substrates for surface imprinting for many reasons including well‐established, numerous hydroxyl groups on the surface, chemical/mechanical stability, nontoxicity, and biocompatibility.…”