Non-aqueous Capillary Electrophoresis Of Basic And Applied Research

Capillary electrophoresis (CE) is a new separation technique, which is considered as one of the powerful Analytical Chemistry branches, and also an important improvement of the separation sciences after high performance liquid chromatography in the early 1980s. In traditional CE, the separation was carried out under the aqueous medium, and mainly used for the analysis of the water-soluable substances. In order to assay the hydrophobic substances, non-aqueous capillary electrophoresis (NACE) method has been brought out and widely developed for recent years. In this dissertation, three aspects on the study and application of NACE methodhas been carried out.1. A non-aqueous capillary method was set up to separate three adenosine monophosphates and four nucleosides. The influencing factors on the sparation, such as the running electrolyte, organic medium and buffer's pH, have been optimized and achieved. With 200 mmol/L Tris/200 mmol/L H₃BO₃/ CH3CN (1:2:3,v/v/v) at pH*10.0 as the electrophoresis solution, 25 kV as the separation voltage and 260 nm as the detection wavelength, adenosine monophosphates and nucleosides have been baseline resolved from each other with. 22 min. The method is simple, fast, accurate and reproducible. It has been successfully employed to assay the adenosine monophosphate products in the reaction samples from the N-phosphate amino acids and adenosine.2. Base on orthogonal experiment design, the running electrolyte, organic medium, buffer's pH and separation voltage in NACE have been optimized as the electrophoresis solution of 40 mmol/L NH4AC in 90% ACN (pH*10.2) and the applied voltage of -25 kV. Under the optimal conditions, three herbicides, 2,4-D, dicamba and 2,4,5-T, have been baseline separated within 16 min. The method has been used to determine the residues of 2,4-D, dicamba and 2,4,5-T in three hundred actual tobacco leaf samples, and the results have been evaluated.3. The separation mechanism of alkali, alkaline metal and ammonium cations in NACE has been investigated under the basical pH value on different inner diameter of capillary. Using MeOH as the organic medium, 4-methylbenzylamine (MBA) as co-ion, acetic acid as negatively charged ligand. The background electrolytes (BGEs) with 20 mmol/L MBA (co-ion) and diferent pH values were prepared by adding HAc in different amounts. MBA was selected due to its greater pKa values than imidazole. Its high pKa values allow us to prepare...