ABSTRACT
Objective: To prepare morin-Cu2+ complex imprinted polymer (CIP) and use the polymer to extract morin from mulberry branch. Methods: Morin-Cu2+ CIPs were prepared in water-methanol polar solvent in the presence of Cu2+, acrylamide as the functional monomer. The CIPs were used as the solid phase extraction sorbent for extracting morin from mulberry branch. Results: The prepared CIPs had specific and selective adsorption on morin, the maximum adsorption capacity was 82 μmol/g, which was much higher than that of the traditional imprinted polymers relying on hydrogen bond and non-imprinted polymers. The separation factors of CIPs to daidzein and catechin were 4.81 and 4.02, respectively. CIPs had a significant enrichment effect on morin in the composition of the mulberry branch solid phase extraction elution solution. Conclusion: Morin-Cu2+ CIPs are excellent material used for the separation and enrichment of morin, the material has good selective adsorption ability and environmental adaptability.
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.
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Objective: To prepare the molecularly imprinted polymer (MIPs) of L-tetrahydropalmatine (L-THP) by the molecular imprinting technique and study on solid-phase extraction. Methods: Using L-THP as template, methyl acrylic acid (MAA) as functional monmer, and ehtylene glycol dimethacrylate (EDMA) as a cross-linking agent to prepare the L-THP-MIPs. A test was conducted to investigate the selectivity and the specificity of solid-phase extraction. Results: The experiment showed that the MIPs had the specific adsorption to L-THP, but did not have the specific adsorption to corydaline the structural analogue with L-THP. Conclusion: The L-THP-MIPs have a good selectivity and the specificity of L-THP.
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Extraction and separation technologies appeared in recent years are particularly reviewed in the principles, features, latest research and application results, and existing problems as well. These new techniques include ultrahigh pressure extraction (UPE), ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), pressurized solvent extraction (PSE), smashing tissue extraction (STE), heating-free extraction (HFE), high-speed countercurrent chromatography (HSCCC), and molecular imprinting technique (MIT). Further research topics and application prospects of these extraction and separation technologies are also suggested, so as to provide the reference for the research and production of modern Chinese materia medica.
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To establish a method for directional separation of dehydrotumulosic acid from the extracts of Guizhi Fuling Capsule with molecular imprinting technique (MIT). Molecular imprinting polymer (MIP) was prepared by sol-gel process with dehydrotumulosic acid as molecular template to study the absorption property. The dehydrotumulosic acid was achieved from Guizhi Fuling Capsule by one-step separation with polymer as filler. The structure of dehydrotumulosic acid was identified on the basis of the spectral data and physicochemical property. The maximum binding capacity (Qmax) of MIP was 9.10 mg/g measured by Scatchard equation and the purity of dehydrotumulosic acid was 90.76% by HPLC. The established MIT for the directional separation of dehydrotumulosic acid from Guizhi Fuling Capsule is simple and benefit to reducing the solvent use during the separation process, which could offer a novel method for the separation and purification of dehydrotumulosic acid.
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An online solid phase extraction ( SPE ) coupled with high performance liquid chromatography (HPLC)-mass spectrometry (MS) method was developed for the separation of 1,3,5,7-tetraacetyl-1,3,5,7-tetraazacyclooctane ( TAT ) and 1 , 3 , 5-triacetyl-1 , 3 , 5-triazacyclohexane ( TRAT ) which are the synthetic intermediates of cyclotetramethylenetetranitramine ( HMX) . In this experiment, molecularly imprinted polymers with TAT as the template were used as SPE sorbents. PC HILIC column was employed in liquid chromatographic separation. The parameters of SPE-HPLC were optimized. Acetonitrile was selected as the loading solution with flow rate of 0. 1 mL/min. After flushed by ethyl acetate, the TAT adsorbed on SPE was eluted by methanol, which was also used as the mobile phase in HPLC separation. The mass spectrometry was coupled with HPLC to identify the corresponding peaks. Under the optimized conditions, the linear detection range of this method was 6. 0 mg/L to 500. 0 mg/L, with the detection limit of 1. 8 mg/L (3σ). The enriching factor was 400 times and TAT recovery was 79%–93% in the standard addition experiment.
ABSTRACT
By the approach of self-assembly and electropolymerization, membrane for Bisphenol A (BPA) has been synthesized with bisphenol A as template molecule, o-aminothiophenol as functional monomer. Based on which, an electrochemical sensor was constructed and its response to BPA was evaluated by cyclic voltammetry. The peak current intensity was linear to Bisphenol A in the range of 6.0×10-7-5.5×10-5 mol/L with a detection limit of 2.0×10-7 mol/L and the RSD <5%(n=9). The response time of stable current was about 2 min. The proposed sensor exhibits good selectivity, reproducibility and stability. The AC impedance technology and chronoamperometry were employed to study the electrochemical characteristic of the membrane. The sensor was successfully applied to the determination of BPA in several samples.