ABSTRACT
Objective: To prepare the molecularly imprinted composite membrane of curcumin by the atom transfer radical polymerization (ATRP) technique and develop a method for the separation and enrichment of curcumin in actual samples. Methods Curcumin MIM were prepared by thermal polymerization method using curcumin as template molecule, methylacrylic acid as functional monmers, cuprous chloride as catalyst, pentamethyldiethylenetriamine as ligand, and polyvinylidene fluoride as base membrane. The microstructure of MIM was investigated by SEM. The maximum adsorption and adsorption equilibrium time of MIM were investigated by static and dynamic adsorption experiment, and the selective penetration capacity was studied. The MIM as membrane material of osmotic device combined with HPLC was used for separation, enrichment and determination of curcumin in samples. Results The results showed that the prepared curcumin MIM had a regular distribution of pores and a uniform size. The maximum adsorption capacity was 3.81 mg/g, and the adsorption equilibrium could be achieved in 15 min. In the selective permeation process of ferulic acid, quercetin and curcumin, MIM had a high selective permeability to curcumin. The average recovery rates of curcumin in ginger, turmeric and curry were (94.100 ± 3.952)%, (98.300 ± 3.637)%, and (97.900 ± 3.133)%, respectively. The RSD was less than 4.2%. The limit of detection was 1.76 μg/kg. Conclusion The prepared MIM is a new material for strong selectivity, separation and enrichment of Chinese medicine curcumin with fast adsorption speed. At the same time, it also provides reference for chemical composition research of other Chinese materia medica.
ABSTRACT
A printed polymer for selective identification of levofloxacin was synthesized on the surface of silica gel with levofloxacin as template molecule. The polymer was characterized by elemental analysis and infrared spectroscopy, and the properties of the polymer were determined by dynamic adsorption and selective adsorption. The results showed that the maximum adsorption capacity of the imprinted polymer was 56.33 mg/g and the imprinting factor was 2.62. The imprinted polymer was applied to quantitative analysis of levofloxacin with molecular imprinted solid phase extraction spectroscopy (SPES). The SPES was carried out in an elaborately designed device with which the interested analyte was extracted by the solid phase extraction medium and the diffuse reflectance spectrum was measured directly on the solid medium without elution. SPES has simplified the operation process and improved the sensitivity. The regression equation of the standard curve was A=0. 0496C+0. 2412, the correlation coefficient (R2) was 0. 9924, the linear range was 0. 25-9.0 mg/L,and the detection limit was 0.24 mg/L. The recoveries of determination of levofloxacin in Pork samples were 89.1%-92.0%, and the relative standard deviations (RSDs) of the three parallel tests were 3.4%-7.9%. Compared with the traditional enrichment and separation technique, this method developed here had some advantages such as miniaturization and integration, high sensitivity and selectivity, low cost, simple operation and rapid detection.