Application Of Microwave-assisted Hydrolysis And Deirvatization In Determination Of Amino Acids And Monosaccharides In Natural Medicines

Microwave Chemistry is an interdisciplinary, which was first reported in the1960s. In the1980s the studies on the microwave chemistry took place inChina. Microwave-assisted chemical process or reaction can greatly shorten thepre-processing or reaction time. Microwave technique has been widely applied invarious fields of chemistry. The microwave hydrolysis and derivatization are based onenergy absorption from microwave irradiation by the polar molecules or ions, whichcan affect on hydrolysis and derivatization of the analytes. Capillary electrophoresis(CE) is a aeparation and detection technology, which was booming by the1980s.Compared with other separation and detection techniques, CE has some advantagessuch as low pollution, small sample amount and low cost. CE is widely appliedto environmental, biological, chemical, medicinal and other fields. In this thesis,amino acids and monosaceharides were separated and determined by CE. Themicrowave-assisted hydrolysis and derivatization were applied to the threament of thesamples. The hydrolysis and derivatization methods were developed.This introduction mainly includes three aspects. First, the various applications ofmicrowave technology in chemistry were introduced; second, the microwave-assistedhydrolysis and derivatization were revised. Finally, the development and applicationof capillary electrophoresis were described.In Chapter2, microwave hydrolysis and derivatization coupled with capillaryelectrophoresis was applied to the separation and determination of11kinds of amino acids in Panax notoginseng (Bark.) F. H. Chen.0.2000g of sample powder,10mL of6mol/L HCl containing1%phenol were added in the digestion versel and purged withnitrogen. The hydrolysis was performed at170oC for20min. The hydrolyzate wasevaporated to dryness and the residue was dissolved with10.00mL0.5mol/L HCl.2,4-Dinitrofluorobenzene was used as derivative reagent and the analytes werederivated at microwave power of260W for30s. The resulting derivatives weredetermined by capillary zone electrophoresis. The optimum experimental conditionsfor the hydrolysis, the derivatization and capillary electrophoresis, such as separationvoltage, pH of the background electrolyte, the borate concentration in the backgroundelectrolyte were examined and selected.11amino acids were separated anddetermined. The actual sample was analyzed. Compared with traditional methods,including the traditional hydrolysis and traditional derivatization methods, theanalytical time was shorter. The analytical results of sample obtained by the presentmethod and traditional methods were similar.In Chapter3, the amino acids in Bupleurum chinense DC. were determined bycapillary micelle electrophoresis. The microwave-assisted hydrolysis andderivatization was applied,4-Chloro-3,5-dinitrobenzotrifluoride (CNBF) was used asderivative reagent.1-Butyl-3-methyl-tetrafluoro-imidazolyl, borate and sodium lauylsulfate were main constituentes of the background electrolytes and micelles wereformed in CE. The optimal conditions of microwave hydrolysis and derivatization,and capillary electrophoresis were studied. Under selected conditions, the18aminoacids were separated and determined. The sample was analyzed and the results weresatisfactory.In Chapter4, the monosaccharide constituents of Cimicifuga foetida L werestudies by microwave-assisted hydrolysis and derivatization method,7monosaccharide constituents were detected.20mg of sample and10mL2mol/Ltrifluoroacetic acid were added into the digestion vessel. The hydrolysis wasperformed at140oC for15min. Filtrate was evaporated to dryness and the residue wasdissolved in water.1–Naphthylamine was used as derivative reagent andmicrowave-assisted derivatization was performed at270W for70s. The experimentalconditions for the hydrolysis, derivatization and capillary electrophoresis, such asseparation voltage, pH of the background electrolyte, the borate concentration in thebackground electrolyte were examized and optimized. In the selected conditions, the detection limits of7monosaccharides were from0.42to1.36μg mL-1. The actualsample was analyzed. The traditional hydrolysis and derivatization methods wasapplied and the results were compared.In Chapter5, monosaccharide components in Tripterygium wilfordii Hook. werestudies by microwave-assisted hydrolysis and derivatization method. Sixmonosaccharides were separated and determined by CE.1-Phenyl-3-methyl-5-pyrazole morpholone was used as derivative reagent. The CEconditions for separation and determination of the analytes were as follows:254nm,21kV, pH=9.0,75mmol/L borate. Microwave hydrolysis conditions are similar to theselected conditions in Chapter3. The limits of detection of the six monosaccharideswere10.12-18.20μg·mL-1. The actual samples was analyzed.