| The reproducibility of capillary electrophoresis(CE) is generally inferior to chromatographic analysis(for example, high performance liquid chromatography and gas chromatography) owing to the instability of electroosmotic flow(EOF, the heart of CE), which limits its application in routine analysis. In this work, we presented a pressure-driven capillary electrophoretic system by the combination of high-pressure pump and a six-way injection valve, where the introduction of a high-precision pressurized flow improved the reproducibility and enhanced the analytical efficiency.In the first chapter, the separation principle, separation mode, operation and detection methods of capillary electrophoresis were introduced in detail.In the second chapter, the design of the pressurized capillary electrophoresis system and its application in the speciation analysis of iodine in table salt with ultraviolet(UV) detector was proposed. In the pressurized capillary electrophoresis, a pressurized flow of electrophoretic buffer at the flow range of 4.5 nL/min-0.81μL/min was introduced into the separation capillary by splitting the conventional flow fed by the high pressure pump whereas the nanoliter sample(below 10 nL) was injected into the separation capillary after splitting. In combination with UV detection,fast separation of iodine species( I-and IO3-) was achieved within 0.3 min and the detection limits for I-and IO3-were 0.014 and 0.015 mg/L, respectively.In the third chapter, a hyphenated method for mercury speciation analysis by the coupling of pressurized capillary electrophoresis and inductively coupled plasma mass spectrometry was developed. Fast separation of mercury species(Hg2+, MeHg and PhHg) was achieved within 10 min in a new separation capillary(75 μm) without any treatment, with 2.0 mM borate(pH=8.3) as the buffer.A conclusion was made on the basis of the above works in the final chapter,followed by the prospect of pressurized capillary electrophoresis in various fields. |
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