| Microchip electrophoresis has many virtues such as low sample consumption,fast analysis speed,easy integration and so on.Fabrication is the basis of microchip electrophoresis technology.The target of portable microchip electrophoresis promotion and application is simplicity,cheapness,high-fast.Injection volume limits the detection of low concentration sample.Combining online or offline concentration methods with microchip has drawn attention to detect low abundance samples.In the first chapter,we elaborates the production of microchip with aspect of materials and fabrication methods and evaluates its advantages and disadvantages.The chapter reviews the principle and application of concentration methods and finally makes simple introduction of the test methods.In the second chapter,we proposed a sandwich structure of glass-PDMS-glass microchip.With glass slide as support materials,deformation of PDMS layer was avoided and at the same time the heat conduction was improved.The fabrication of microchip is simple,and bonding step is avoided.With the cross contact of two microchannels as the injection port,the salple injection voltage and injection time is optimized using 1.0 ×10-6 mol/L sodium fluorescein as probe.Under the optimized conditions,the two kinds of DNA Marker fragments can be rapidly separated respectively.In the third chapter electrokinetic concentration of fluorescein sodium probe was conducted firstly,and the concentrated sample is off-line transferred to the PDMS-glass-PDMS sandwich microchip with laser induced fluorescence detection.Using 1.0×10-6 mol/L sodium fluorescein as low conductance for sample solution,the influence of eletroosmotic flow is discussed,choosing 0.4%hydroxyethyl cellulose as inhibitor.With the stacking,the signal intensity of 1.0 × 10-7 mol/L sodium fluorescein was 18 times improved.With brilliant blue as the stacking band indicator,detection of 1.0 ×10-8 mol/L sodium fluorescein was achieved. |
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