Electrokinetic Micro-Analytical System And Its Applications In Pharmaceutical Analysis

Theories of capillary zone electrophoresis, microfluidic chip analysis and monolithic capillary electrochromatography and their applications in pharmaceutical analysis were investigated and demonstrated in the paper.1 Theoretical studies on CE and the applications of CE in pharmaceutical analysis1.1 An expression that permits the determination of the resolution froman electropherogram was firstly formulated. The least length of a capillary column was t_sv₁. The expression should be useful in the optimization of common chromatographicanalysis and CEC.1.2 The conflicts between the motivity of EOF and the experimental phenomena in CE were described, and a hypothesis on the mechanism of EOF development was presented for the first time: under the applied voltage, the diffuse layer of the EDL acted as a stationary phase and had a chromatographic function to the ions in buffer, the co-ions in buffer which had the same charge of the ions in the diffuse layer were "lubricated", while the counter-ions in buffer were "retarded". So, the balance of the push forces to the bulk buffer in two directions was broken and a net push force produced, and thus formed the motivity of EOF in the direction of the electrophoresis of the ions in the diffuse layer. The inhibition of the capillary inner wall to the bulk solution was also played an important role in the process of EOF. The flat profile mechanism and how the capillary inside diameter, buffer concentration, temperature and added modifiers, etc. influenced EOF were re-explained according to the assumption, and this will be helpful for the design of different kinds of monolithic capillary electrochromatographic bed and the optimization of its operational condition.1.3 Factors that influenced the reproducibility in CE and its controls were summarized and discussed. The reproducibility of the results could be improved when the analytical process was synthetically controlled.1.4 The content of troxerutin in troxerutin preparations and the contents of Cytidine, Adenosine, Guanosine and Undine in Banlangen injection were determined by CE. Troxerutin and its impurities were also identified by CE-MS/MS.2 The establishment of microfluidic chip analytical systems and their applications in pharmaceutical analysisA small-scale LIF detector with simple orthogonal structure for the chip analysis was developed. It was seasoned with chips of different size and channel network. The position of the detection could be adjusted conveniently. The replacement of the laser and the filter with different wavelength could adapt to the corresponding condition. The turn-induced broadening named turn effect was observed through a set of homemade micro=imagining system. The expression t_inj=(l_inj·E_sep)/(l_sep·E_inj)·t_m, which described the relationship between the injection time and the migration time of a component in chip analysis, was given. Vitamin B₂ was analyzed with excited wavelength 473nm and emission wavelength 520nm. The design of the channel structure, the treatment of the channel, the operational condition optimizing and the reproduction of the results were investigated. The primary separation of amphetamine kind drugs on microchip was also carried out. A set of UV detection system for chip analysis was also established since many medicines had UV absorbanee. Three components in sulfamethoxazole, sulfadiazine and trimethoprim tablets and three nueleotides in aweto were analyzed by the designed UV system, using the hybridized chip with a length of fused silica capillary was conglutinated to the channel end. The results demonstrated the feasibility of chip analysis for pharmaceutical analysis. Chip analysis is of value for further investigation.3 Theoretical study on CEC and the applications of CEC in pharmaceutical analysis3.1 On the assumption that component electrophoresis factor basically did not have parametric interaction with its chromatographic behavior in CEC, two new retention factor expressions k_CEC=k′-μ_ep/(μ_eo+μ_ep)(â… )and k_CEC=k′-(μ_ep-μ_ep⁰)/(μ_eo+μ_ep)(â…¡) was deduced, and they can complement each other. Two expressions of component retention factor in literatures k_CEC=k′+k′μ_ep/μ_eo+μ_ep/μ_eo(â…¢) and k_CEC=(k′-μ_ep/μ_eo)/(1+μ_ep/μ_eo)(â…£) were diseussed. Wrong citation of the component electrophoresis distance expression in the deduction of expression (â…¢) was pointed out. The expression (â…¡) could make up the limitation of above expressions, especially whenμ_eo=0. Expressions (â… )and (â…¡)could reflect the integrated effect of component chromatographic and electrophoresis behaviors. 3.2 Four kinds of MLCEC column with or without AMPS as an EOF initiator using BMA and LMA, respectively, were prepared. The performance of the EOF on the four columns was investigated. The results indicated that the performances of the two columns without AMPS were consistent when modified using anionic surfactant. The EOF on the LMA column with AMPS was smaller and not stable causing poor peak shape. EOF initiator seems only applicable to the short chain stationary phase.3.3 The separation of three components in sulfamethoxazole, sulfadiazine and trimethoprim tablets and the determination of two nucleotides in aweto, and troxerutin in troxerutin tablets were performed by the BMA column with AMPS. The reproducibility and the ruggedness of MLCEC were better than those of CE though with lower column efficiency. The results indicated that M.LCEC had the broad prospects in pharmaceutical analysis.