Application And Construction Of Molecular Imprinted Solid Phase Extraction Column On Microfludic Chip

As a developing new field of analytical chemistry recently, the finally goal ofminiaturized total analysis system (μ-TAS) is miniaturization and integration, namely, allprocess of analytical chemistry could be performed on microchip. At present, the researchand innovation of microchip mostly concentrated in the separation and detection, mixingand reaction. How to carry out sample pretreatment on a microchip is relatively weakaspect, especially for those complex matrix samples or trace components. Therefore, todevelop sample pretreatment technology is a pressing task before practical use of microchipsystem, and is also the bottleneck that must be broken through for integration of developingμ-TAS.In recent years, the frequent appear of food safety events make people pay muchattention on food safety. The reasons for food safety are mostly illegal use of non-ediblesubstances, thus including the industrial dye aurmaine O. These illegal substances arealways trace states and difficult to be detected under the background of complex matrix.Molecularly imprinted solid phase extraction technology, which has high selectivity andgood adsorption, can absorb target molecules selectively, thus overcome endogenousinterference of complex samples. Therefore, molecularly imprinted solid-phase extractiontechnology was combined with PDMS-glass microchip in this paper to build a novel solidphase extraction microchip device, and with the new device, the industrial dye auramine Owas detected in shrimp successfully. In this paper, a novel molecular imprinted solid phase extraction column (MISPE) was prepared by UV-initiated in situ polymerization in acapillary, for the determination of auramine O. The properties of the MISPE column wereinvestigated under the optimized conditions by High performance liquid chromatography(HPLC). Integrating MISPE column and PDMS-glass microchip together, a combinationmicrochip with MISPE column was established. On the PDMS-glass chip, there are severalreserves and micro channels, which are used for sample pretreatment, sample injection,separation and contactless conductivity detection. After the chip was connected with themicropumps, the procedures for solid phase extraction, such as sample loading, washing,sample injection and elution, are automatically performed on this integrated microchip. Atthe end of separation channel, the elution is detected with contactless conductivity detectionby electrophoretic injection mode. The results showed that the microchip system wasreliable and applicable to the analysis of auramine O in shrimp. This paper includes thefollowing three parts:1. This section firstly overviewed the microfluidic chip technology and its productionmaterials, methods and types of detector. Secondly, the classification and preparationmethods of molecular imprinted technology were described. At the same time, itemphasized on the technology of MISPE coupled with microchip and types of modes.Finally combining the current situation of food safety, and put forward the thesis researchideas and meaning.2. A method combing molecular imprinted solid phase extraction of auramine O wasprepared. Using auramine O as template and methacrylic acid and ethylene dimethacrylateas function monomer and cross-linker, respectively, the capillary column was prepared byUV-initiated in situ polymerization. The types of porogen and molar ratio of template,monomer and cross-linker was optimized in this paper. The properties of the6cm longcolumn were investigated coupled with HPLC and scanning electron microscopy (SEM).The results showed that the enrichment factor was73.5, and capacity of the column was0.722μg/mg. The recoveries of auramine O were90.5-92.4%with RSD ranging from2.1-4.4%, and the limit of detection was17.85μg/kg. The results indicated that theprepared molecularly imprinted capillary column were reliable and applicable to the analysis of auramine O in shrimp.3. A device of molecularly imprinted solid phase extraction on microfluidic chip wasbulid. A simple PDMS-glass mirofluidic chip for on-line pretreatment and contactlessconductivity detection, which consisted of a0.17mm-thick glass cover and a PDMSsubstrate, was presented in this paper. An equal solid phase extraction capillary monolithiccolumn was coupled to reserved position on PDMS-glass chip. With micropumps, sampleextraction, injection, separation and detection were automatically performed on thisintegrated microchip, yield on-line enrichment factor of about12with LOD being2.5μg/mL. At the same time, the optimized electrophoresis conditions were discussed, and theoff-line enrichment factors were20. The results indicated that microchip system is reliableand applicable to the analysis of auramine O in shrimp.