| Capillary Electrophoresis (CE) is a relatively recent separation technique with the advantages of high efficiency, short analysis time, small sample volume, low operation cost, and the possibility of rapid method development. Just for its specific features, it has received considerable attention within the analytical, medical and biochemical communities. And now it has become a very active frontier in analytical chemistry. CE has been successfully applied to the separation of various compounds ranging from ion to neutral molecule, from small molecules to large biopolymers, especially to the separation of polypeptides, proteins and DNAs. With the accomplishment of human genome project and the advent of pretonome, transcriptome and metabolome, CE has become one of the most useful techniques in these fields. In this dissertation, two modes of CE, including capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC), were investigated and applied to the separation of cefaclor and its isomer, sialic acid, polyamines and hyaluronic acid. This dissertation was divided into five chapters.Chapter 1 provided a comprehensive review of CE in terms of the principles, separation modes, injection, detection and typical applications.In chapter 2, two methods (including CZE and MEKC) for the separation of cefaclor and δ-3-cefaclor were developed. In the CZE method, 4-sulfonic calix[6]arene (SCX6) was used as one selectivity modifier. The concentration of SCX6 and pH of the background buffer were found to be important parameters in the separation of cefaclor and δ-3-cefaclor. In the MEKC method, the influences of different electrolytes, anionic surfactants and organic modifiers on the separation of cefaclor and 5-3-cefaclor were studied. The two methods were applied to separate and determine active ingredient in cefaclor for oral dry suspension successfully.In chapter 3, two on-line concentration CE methods for determination of sialic acid in saliva were developed. Firstly, an on-line concentration MEKC method was developed. The influences of different surfactants (sodium dodecyl sulfate, sodium cholate and sodium deoxycholate), different electrolytes (sodium phosphate monobasic, sodium tetraborate and 3-cyclohexylamino-1-propane sulfonic acid), buffer pH and organic modifiers (methanol and acetonitrile) on the determination of sialic acid were studied. The effects of the composition ofsample matrix and injection time on the concentration efficiency of sialic acid were also studied. Secondly, an on-line concentration CZE method was developed. In the method, 40 mM phosphate solution was as buffer, 66.7 % acetonitrile in water as sample matrix and injection time 100 s. The influences of different electrolytes (sodium phosphate monobasic, sodium tetraborate and 3-cyclohexylamino-1-propane sulfonic acid), buffer pH and organic modifiers (methanol and acetonitrile) on the determination of sialic acid were studied. Calibration line, detection limit and reproducibility of the developed two methods were investigated and the two methods were applied to determine sialic acid in saliva successfully.In chapter 4, a new MEKC method for the separation and determination of polyamines in urine after pre-column derivatization with benzoyl chloride was developed. For derivatization, sodium hydroxide solution and benzoyl chloride were added to the sample, then diethyl ether was used to extract the derivatized analyte after concussion of the mixture, at last the diethyl ether solution was removed and air-dried. The influences of different surfactants (sodium dodecyl sulfate, sodium cholate and sodium deoxycholate), different electrolytes (sodium phosphate monobasic, sodium tetraborate and 3-cyclohexylamino-l- propane sulfonic acid) and buffer pH on the separation of polyamines were studied. Under the conditions(wavelength 254 nm, applied voltage 25 kV, buffer 30 mmoI/LSDS - 20 mmol/L borax(pH 9.2) ), spermine^ putrescine and spermindine in urine were separated and determined successfully. The linear calibration ranges of spermine, putrescine and spermindine were 48-1440 mg/L, 16.7-500 mg/L, 40-1200 mg/L respectively and the detection limits achieved at three times the signal-to-noise ratio were 10 mg/L> 5 mg/L> 8 mg/L respectively.In chapter 5, a MEKC method for the rapid separation and determination of hyaluronic acid in Antin Whitening Vitatizing Cream and Avon Maximum Moisture Super Hydrating Complex with UV detection at 200 nm was proposed. The influences of different surfactants (sodium dodecyl sulfate, sodium cholate and sodium deoxycholate), different electrolytes (sodium phosphate monobasic, sodium tetraborate and 3-cyclohexylamino-l-propane sulfonic acid), buffer pH and organic modifiers (methanol and acetonitrile) on the determination of hyaluronic acid were studied. Hyaluronic acid was separated and detected in less than 10 min with 30 mmol/LSDS - 20 mmol/L borax (pH 9.2) as buffer and applied voltage 25 kV. In the method, sample pretreatment is simple, just dissolving the sample in hot water and filtering the samplesolution. |
