Bollrosendahl5956

OT-CEC separation efficiency of the drugs was dramatically enhanced because the block co-polymer could self-assemble in the solution and form pseudo-micelles, which further increased the interactions between the P(St-GMA) and these drugs. Our results not only reveal the great potential of block co-polymer coatings in OT-CEC for the analysis of drugs in real biological samples, but also serve asa platform for the preparation of diverse block co-polymers to be used in OT-CEC analysis. We believe that in the near future, the peak tailing problem in OT-CEC analysis can be resolved by using the designed unique block co-polymers, which possess a greater number of functional sites, as coatings and by appropriately tuning the interactions between the analytes and the coatings.Alzheimer's disease (AD) is the most common cause of dementia in elderly individuals. Currently, acetylcholinesterase inhibitors (AChEI) are the most effective clinical treatment for AD. AChEIs in natural products may have therapeutic potential and should be screened for use in AD treatment. The authors describe a simple and reliable method for AChEI screening by capillary electrophoresis (CE). A hexadimethrine bromide (HDB) solution was pushed into a capillary (0.015 MPa×10 s) and incubated for 5 min. The capillary was flushed with deionized water for 5 min to remove free HDB, followed by plugging with an acetylcholinesterase (AChE) solution. After a 5 min incubation, the AChE was immobilized on the positively charged coating by ion binding, and the micro-reactor was created. The substrate solution, acetylthiocholine iodide (AThC), was injected into the capillary and incubated in the micro-reactor for 1 min. buy SCH 900776 The unreacted substrate and the enzymolysis product were separated by CE. Gastrodin, an important component of Gastrodia elata, can inhibit AChE activity. After a certain amount of gastrodin was spiked into the substance solution, the peak area of the product decreased. Greater peak area reduction indicated stronger inhibition of AChEI. We observed good reproducibility of the product peak, with relative standard deviation (RSD) values less than 5.3%. The micro-reactor can be reused up to 300 times, which greatly improves efficiency. When the concentration of gastrodin was 5.24 μmol/L, the inhibition rate of AChE reached 64.8%. The IC50 of gastrodin was (2.26±0.14) μmol/L (R2=0.9983), which was consistent with the result of traditional UV method (2.09±0.18 μmol/L). If the function of the micro-reactor deteriorates, it can be conveniently renewed by flushing the column to remove the enzyme and repeating the AChE immobilization protocol. The proposed method is simple, efficient, and low cost, and can be used to screen AChEI from natural products, thus contributing to the improvement of AD treatment.As a class of new porous crystalline materials, covalent organic frameworks (COFs) are attracting the attention of a large number of scientists. Because of their large specific surface area, low density, high stability, and tunable pore size, COFs have been widely applied in many fields, including analytical chemistry. Open-tubular capillary electrochromatography (OT-CEC) is a mode of capillary electrochromatography. In recent years, a variety of materials such as porous organic frameworks have been used as the stationary phase for OT-CEC to overcome the disadvantages of low phase ratio and column capacity, thereby improving the separation efficiency. However, there are a few reports on the use of COFs as the stationary phase to improve the separation efficiency of OT-CEC. Environmental endocrine disruptors (EEDs) are a large class of exogenous chemicals that can disturb the effect of the normal endocrine substances and adversely affect the endocrine and reproductive systems of human beings. Considering the wr than 0.99. For the four analytes, the limits of detection and limits of quantitation were in the ranges of 0.13-0.23 mg/L and 0.45-0.60 mg/L, respectively. The intraday, interday, and column-to-column relative standard deviations (RSDs) of the migration time and peak area were less than 9.4%. These results revealed that the established method has good repeatability and high stability, thus being suitable for the separation and detection of nitrophenol EEDs. The mechanism studies revealed that the pore size of ACOF-1 was the main factor influencing the separation behavior of each analyte. This work demonstrated the feasibility of using capillary electrochromatography with COFs as the stationary phase for the separation and detection of EEDs. Future research will continue to focus on the preparation of COF-coated capillaries and their application to OT-CEC separation and determination of EEDs.A capillary coated with mixed polymer brushes that shows switchability toward lysozyme adsorption was developed. This capillary was applied for the on-line preconcentration of lysozyme by capillary electrophoresis (CE) in order to enhance the detection sensitivity. First, poly(2-methyl-2-oxazoline) (PMOXA) and poly(acrylic acid) (PAA) were synthesized by cationic ring-opening polymerization and reversible addition-fragmentation chain transfer (RAFT) polymerization, respectively. Then, glycidyl methacrylate (GMA) and PMOXA were used to prepare poly(2-methyl-2-oxazoline)-random-glycidyl methacrylate (PMOXA-r-GMA) via radical copolymerization, and poly(acrylic acid)-block-poly(glycidyl methacrylate) (PAA-b-PGMA) was obtained by the RAFT polymerization of GMA and PAA. A mixed solution of PMOXA-r-GMA and PAA-b-PGMA at a certain mass ratio was then injected into the capillary. Subsequent annealing provided capillary materials coated with mixed polymer brushes based on PMOXA and PAA. X-ray photoelectron spectroscopyerday relative standard deviations (RSDs) for the peak areas were 2.9% and 4.1%, respectively. The intraday and interday RSDs for the migration times were 0.9% and 2.1%, respectively. The developed method for the preparation of the coated capillary with good stability only needs one step in this work, and this research will supply a simple and effective way to analyze trace protein by CE.