In this paper,the poly(amidoamine) dendrimer modified silica was used to immobilize aminoacylase by glutaraldehyde as crosslinking agent.The influence of different generation of PAMAM,glutaraldehyde concentration,reaction time and temperature on enzymatic activity of the immobilized enzyme were evaluated.The enzymatic properties of the immobilized enzyme were also evaluated.The results showed that the immobilization efficiency increased with the generation of PAMAM increasing,and the immobilized enzyme remained high activity.

PAMAM dendrimer modified silica was prepared for trypsin immobilization.The generation of PAMAM and the immobilization conditions were investigated.The results showed that the 3.0 G PAMAM dendrimer modified silica would provide high immobilization yields and enzymatic activity and it was employed for trypsin immobilization.The optimum temperature and pH of the immobilized enzyme were 60℃ and 9.0,respectively.The Km value for casein was 7.76 mg/mL.Compared with free enzyme,the immobilized enzyme has better thermo-stability,and it also features good storage stability and reusability.

Microwave technology was adopted for grafting of polyamidoamine (PAMAM) onto the surface of silica. Fluorescence microscopy, elemental analysis (EA), Fourier transform infrared spectroscopy (FTIR) and titrimetry were used to characterize the structure and composition of the dendrimer-grafted silica surface. The results indicated that the number of amino groups and the percentage of nitrogen increased with increasing PAMAM generation, thus, the microwave assisted protocol was found to be effectively. Bovine serum albumin (BSA) was used as a model biologic molecule to react with the dendrimer-grafted silica by chemical bonding through glutaraldehyde. The immobilization efficiency for BSA increased with increasing PAMAM generation.

Fluorescein isothiocyanate was used as a label to show that a 3-aminopropylmethyldimethoxysilane (KH 550)-modified capillary column was prepared by microwave irradiation. A bromoacetate-substituted β-cyclodextrin (Br-β-CD) was successfully bound to the KH 550-modified column as a chiral stationary phase for open tubular capillary electrochromatography. Compared with conventional synthesis, the microwave-assisted process significantly decreased the preparation time of the stationary phase from 16 h to 40 min. Baseline chiral separation of 1-phenyl-1,2-ethanediol was achieved using the Br-β-CD modified column.

The capillary enzyme micro-reactor was prepared by immobilizing aminoacylase on the inner wall of capillary with glutaraldehyde as a cross-linking agent.The enzymatic hydrolysis of N-acetyl-DL-methioine in the prepared micro-reactor was evaluated by capillary zone electrophoresis.The results showed that high efficiency of the enzymatic hydrolysis could be obtained at pH 7.5 and 37 ℃ for 10 μg/mL N-acetyl-DL-methioine with a flow rate of 4 μL/min in a 15 cm capillary enzyme micro-reactor.The enzyme micro-reactor was stable while its activity decreased less than 8.66% within 10 days.

Polyamidoamine dendrimer (PAMAM) is one of a number of dendritic polymers with precise molecular structure, highly geometric symmetry, and a large number of terminal groups. In this study, different generations of PAMAM (G0–G4) were introduced onto the inner wall of fused-silica capillaries by microwave irradiation and a new type of glucose oxidase (GOx) capillary enzyme microreactor was developed based on enzyme immobilization in the prepared PAMAM-grafted fused-silica capillaries. The optimal enzymolysis conditions for β-d-glucose in the microreactor were evaluated by capillary zone electrophoresis. In addition, the enzymolysis efficiencies of different generations of PAMAM–GOx capillary enzyme microreactor were compared. The results indicate that enzymolysis efficiency increased with increasing generations of PAMAM. The experimental results provide the possibility for the development and application of an online immobilized capillary enzyme microreactor.

Microwave irradiation was introduced into the preparation of poly (amidoamine) (PAMAM) dendrimer modified open-tubular capillary electrochromatographic column. Compared with the conventional method, the preparation procedure was simple and rapid. At the pH range of 5.7 - 8.0, electroosmosis flow of the obtained columns was decreased gradually with the increase of PAMAM generations. The separation of alanine and proline was demonstrated in the obtained columns. The results showed that the resolution of the two components was increased with the increase of the generation of PAMAM. Baseline separation could be achieved in PAMAM G3 modified column. The reproducibility and stability of the column were satisfactory.

The capillary column modified by sulfated β-cyclodextrin intercalated in layered double hydroxides was prepared for open tubular capillary electrochromatography and was applied to separate the racemoid of 1-phenyl-1,2-ethanediol under the optimized conditions.