| Chemiluminescence (CL) analysis has been widely used in many fields due to its attracting features including simplicity, low detection limit, wide linear dynamic range, rapid analysis speed and inexpensive instruments. However, the relatively poor selectivity of the CL method itself limits its direct application to the analysis of analyte in complicated sample. Great efforts were made to improve the selectivity of CL analysis mainly from two aspects. One aspect was to combine CL method with some separation techniques such as high performance liquid chromatography (HPLC) and capillary electrophoresis (CE), but these methods required relatively complicated and expensive instruments. The other aspect was to combine CL method with special molecule recognition, including chemistry recognition, enzyme recognition, antibody-antigen recognition, nucleic acid recognition, DAN recognition, protein recognition and so on. The main problem existing in these methods is their poor stability.Molecularly imprinting technology (MIT) is a novel molecule recognition technology, which prepares the polymer that has special recognition and selectivity function for template molecule. Molecularly imprinted polymer (MIP) not only has excellent special recognition capacity compared with enzyme-substrate, antibody-antigen, receptor-ligand, but also has attractive features such as physical robustness, high strength, resistance to elevated temperatures and pressures, and inertness towards acids, bases, metal ions and organic solvents. Due to the high selectivity and stability of the MIP, MIP has been applied in several analytical fields such as sensor devices, chromatography separation, mimic enzyme, membrane, immune analysis etc. Using MIP as recognition element in FIA-CL sensor, the selectivity and sensitivity of the CL method would be greatly improved due to the special recognition capacity and binding capacity of MIP respectively.The thesis is divided into two parts. Part one describes MIT in details and reviews recentdevelopment and application in analytical chemistry during recent ten years. Part two includes two aspects. The first aspect describes the studies of CL sensors using MIP as recognition elements respectively. The second aspect describes the application of MIP as recognition elements in SPE combined with CL analysis for analyte determination.1. Determination of hydralazine with flow injection chemiluminescence sensor using molecularly imprinted polymer as recognition elementA novel flow injection chemiluminescence (CL) sensor for hydralazine determination using molecularly imprinted polymer (MIP) as recognition element is reported. Hydralazine-MIP was prepared through non-covalent copolymerization using methacrylic acid (MAA) monomer, hydralazine template and ethylene glycol dimethacrylate (EGDMA) cross-linker. Particles of the MIP were packed into a v shape glass tube for on-line adsorption of the analyte of hydralazine. The adsorbed hydralazine could be sensed by its great enhancing effect on the CL reaction between luminol and periodate. The CL intensity is linear to hydralazine concentration in the range from 2*10"9to 8X10'7g/mL. The detection limit is 6xlO"log/mL (3 0 ) and the relative standard deviation is 2.8% (n=7) for 8X 10'9g/mL hydralazine. The selective experiment showed that the selectivity and sensitivity of the CL method could be greatly improved when MIP was used as recognition element in the flow-injection CL sensor. The sensor was reversible and reusable. It could be used for more than 100 times. It has been used directly to determine the hydralazine in human urine.2. Flow-injection chemiluminescence sensor for determination of isoniazid in urine sample based on molecularly imprinted polymerIn this paper, molecularly imprinted polymer (MIP) of isoniazid is synthesized through thermal radical copolymerization of metharylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) in the presence of isoniazid template molecules. A novel flow injection chemiluminescence sensor for isoniazid determination is developed by packing the isoniazid-MIP into the flow cell as recognition elements. Isoniazid could be selectively adsorbed by the MIPs and the adsorbed isoniazid was sensed by its great enhancing effect on the weak CL reaction between luminol and periodate which were mixed in the flow cell. The enhanced CL intensity is linear in the range 2*10'9 to 2xlO"7g/mL and the detection limit is 7><10"10g/mL (3a) isoniazid with a relative standard deviation 2.8% (n=9) for 8xl0'VmL. The sensor is reversible and reusable. Ithas a great improvement in sensitivity and selectivity for CL analysis. As a result, the sensor has been successfully applied to determination of isoniazid in human urine. At the same time, the binding characteristic of the polymer to isoniazid was evaluated by batch method and the dynamic method respectively.3. A chemiluminescence sensor for determination of metformin in urine sample based on molecularly imprinted polymerIn this work, molecularly imprinted polymer of metformin was synthesized and a chemiluminescence sensor was prepared using the polymer as recognition material for determination of metformin. NBS and fluorescein reacted with metformin to produce strong CL. The CL intensity was linear to metformin concentration in the range from 2><10" to 8x10" g/mL. The detection limit was 6xl0"9g/mL and the R.S.D. was less than 5% (n=9). The selective experiment showed that it could greatly improve the selectivity of CL method when MIP was applied to CL. The sensor was reversible and could be used for more than 100 times. It has been used to determine the metfomin in human urine.4. Molecularly imprinted on-line solid-phase extraction combined with flow-injection chemiluminescence for the determination of tetracyclineA molecularly imprinted polymer solid phase extraction (MISPE) method combined with flow-injection chemiluminescence (FI-CL) for tetracycline (TC) determination has been developed. A molecularly imprinted polymer (MIP) of tetracycline was synthesized and particles of this MIP were packed into a polytetrafluoroethylene (PTFE) tube. This tube was employed as MISPE micro-column and was connected into the sampling loop of the eight-way injection valve for tetracycline preconcentration and extraction. After the sample flowed through the MISPE micro-column, tetracycline was adsorbed and preconcentrated on the MIPs. Then eluent (CH3CN:HNO3 (O.Olmol L"1) = 4:1, v:v) was used as carrier for extracting the adsorbed tetracycline to react with cerium (IV) and rhodamine B mixed in the flow cell to produce strong CL. The conditions of preconcentration, elution and CL reaction were carefully studied. CL intensity was linear with tetracycline concentration from 4x 10"9 to 4x 10"7 g mL"1 and the detection limit was lxlO"9g mL"1 (3o) with a relative standard deviation (R.S.D.) 2.4% (n=9). The selectivity of MISPE micro-column and binding capacity of the MIP were evaluated. However, the MIP micro-column interacted indiscriminately with oxytetracycline with a 49±2% binding. Anintermediate step of differential pulsed elution (DPE) using 3% acetic acid as eluent was employed to remove oxytetracycline and other structural analogues. This method has been successfully applied to determinate tetracycline in fish sample. |
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