A novel method to prepare monolithic molecular imprinted polymer fiber for solid-phase microextraction by microwave irradiation.

In this paper, a new approach to prepare monolithic molecularly imprinted polymer (MIP) fibers for solid-phase microextraction is proposed with the help of microwave irradiation. Imprinting polymerization was carried out within silica capillaries in 4.5 min, using dimethyl phthalate (DMP) as a template molecular, α-methacrylic acid as a functional monomer and ethylene dimethacrylate as a crosslinker, acetonitrile as the porogenic solvent. The synthesis was optimized by varying the ratio of template/monomer and different volume of porogen. The resulted MIP fibers were obtained after silica being etched away with a controlled length of 1 cm, and subsequently characterized by SEM. In order to increase the selective extraction of DMP, factors affecting the extraction including extraction time, salt concentration, desorption time, and desorption solvents were investigated for solid-phase microextraction procedures in detail. The selectivity coefficients, defined as the extraction amount ratio of MIP to its nonimprinting fiber, were 5.6, 2.6, and 1.4 for DMP and its counterpart including dibutyl phthalate and di-n-octylo-phthalate, respectively. The resulted fibers were also applied to detect DMP, dibutyl phthalate, and di-n-octylo-phthalate in bottled beverage samples coupled to HPLC and resulted in relative recoveries of up to 73.8-98.5%, respectively.

[The effect of four immunosuppressive drugs on oral manifestations after organ transplantation].

PURPOSE: To assess the prevalence of oral manifestations in a group of allogenic liver, kidney or haematopoietic stem cell transplantation recipients and patients, and analyze the possible oral manifestations associated with the use of 4 immunosuppressive drugs. METHODS: One hundred and eighteen patients submitted to liver, kidney and hematopoietic stem cell transplantation who used tacrolimus， sirolimus，cyclosporine or mycophenolate mofetil were enrolled. Through a questionnaire survey and oral examination, their oral manifestations were recorded, and the possible statistical associations with immunosuppressive drugs were analyzed using SPSS 21.0 software package. RESULTS: The prevalence of oral lichenoid lesions and cheilitis for the group of patients using tacrolimus after transplantation was significantly lower than the group of patients who did not used the agent(P＜0.01). The prevalence of oral lichenoid lesions for the group of patients who used cyclosporine was significantly higher than the group of patients who did not used the drug(P＜0.05), and the prevalence of cheilitis for the group of patients who used cyclosporine was significantly higher than the group of patients who did not used the drug(P＜0.01). The prevalence of oral lichenoid lesions and cheilitis for the group of patients who used tacrolimus was significantly lower than the group of patients who used cyclosporine(P＜0.01). The group of patients who used mycophenolate mofetil after transplantation had a significantly lower prevalence of dry mouth than the group of patients who did not used the drug(P＜0.01). The prevalence of oral manifestations in patients with sirolimus after transplantation was not significantly reduced. CONCLUSIONS: The use of tacrolimus improved the symptoms of oral lichenoid lesions and cheilitis and the effect was better than cyclosporine after transplantation. The use of mycophenolate mofetil improved dry mouth after organ transplantation.

A sensitive electrochemical sensor based on ZIF-8-acetylene black-chitosan nanocomposites for rutin detection.

Herein, we fabricated a sensitive rutin electrochemical sensor via modifying glassy carbon electrode (GCE) with zeolitic imidazolate framework-8 (ZIF-8) and acetylene black (AB) in the presence of chitosan (CS). The electrochemical activity and experimental parameters of the ZIF-8-AB-CS/GCE sensor were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimal conditions, the sensor presented a reasonable linear response in the range of 0.1-10 µM with a limit of detection (LOD) as low as 0.004 µM (S/N = 3). The sensor possessed good reproducibility and high stability, and was successfully applied to detect rutin tablet samples with satisfactory results, which was attributed to the synergistic effect between ZIF-8 and AB. Meanwhile, the sensor displayed a potential application for detection of other analytes in real samples. Furthermore, a probable interaction mechanism was proposed to account for the interaction between rutin and the nanocomposite electrode, which was not discussed in previous reports.