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Imprinting Technique Combined With Chemiluminescence Imaging And Fluorescence Optical Fiber Sensor

Posted on:2009-01-26Degree:DoctorType:Dissertation
Country:ChinaCandidate:L WangFull Text:PDF
GTID:1118360272972658Subject:Analytical Chemistry
Abstract/Summary:PDF Full Text Request
Molecular imprinting belongs to the category of host-guest chemistry in super-molecule chemistry. It is an interdiscipline subject, which origins from macromelocular chemistry, biochemistry, material chemistry, etc. Molecular imprinted polymers (MIPs) are such a synthetically man-made receptor: it owns the cavities which match up substrate molecules in space and can recognize the substrate molecules through the ordered functional groups. Compared with the routine and traditional medium used for separation and analysis, the outstanding character of MIPs based on molecular recognition is its excellent selectivity to the substrates. Further more, MIPs are highly stable and able to bear high temperature, high pressure, acid or alkaline condition, and organic solution. Due to their predetermination, specific recognition and practicability, MIPs have been largely put into use in catalysis, material chemistry, separation and biomimic sensor.A typical imprinting system consists of a print molecule, at least one type of functional monomer and crosslinker, and a porogenic solvent. To induce radical polymerization an appropriate initiator is included as well. In their most common format, MIPs are prepared in the form of a macroporous monolith that is then ground and sieved to appropriate particle sizes. The grinding and sieving process is time-consuming and yields only moderate amounts of 'useful' product. The MIP particles are also irregularly shaped and are not ideal. Although suspension polymerization and seed polymerization can provide spherical, molecularly imprinted polymer beads, they require either use of special dispersing phases/surfactants, or complicated swelling processes. Precipitation polymerization was a more general and simple imprinting method applicable to a wide range of print molecules giving uniform MIP spheres.The research work of the dissertation is made up of two sections of development of MIP-chemiluminence (CL) imaging assay, MIP-fluorescence optical fiber sensor assay. In the first part, imprinted uniform microspheres were synthesized by precipitation polymerization against several templates. The simple and specific methods have been developed coupled of chemiluminescence (CL) imaging assay. In the second part, fiber optic fluorescence sensors have been developed by combinding MIP and fiber optic fluorescence technology. Although MIP has many advantages, a number of problems still exist. One of the main disadvantages is the difficulty in removing the entire template analyte molecule, even after extensive washing. In this part, we are aiming to resolve the problems through oxidizing the template to a compound that can be detected with higher sensitivity. The oxidization reaction could change the template molecular structure and made the compound washed off easily. As a result the cavities can be released and retain their memory for the target analyte. Details are presented in this thesis as follows:Part One MIP-CL imaging assayChapter 1 The development of the molecular imprinted technologyThis review summarizes recent research efforts on the development of molecularly templated (sometimes called molecularly imprinted) polymers. It's contained the progress of MIPs in recent years, the principle of imprinting procedure, the method of synthesiz and MIPs' applications.Chapter 2 CL imageing assayThe development, applicationd and the trend of the CL imageing method were reviewed in this chapter.Chapter 3 Molecular imprinted polymer-based chemiluminescence imaging for the detection of trans-resveratrolImprinted uniform microspheres were synthesized by precipitation polymerization against trans-resveratrol. The conditions of polymerization were carefully studied. Microtiter plates (96 wells) were coated with polymer microspheres imprinted with trans-resveratrol, which were fixed in place using poly(vinyl alcohol) (PVA) as glue. The amount of polymer-bound trans-resveratrol was quantified using imidazole (IMZ)-catalyzed peroxyoxalate chemiluminescence (PO-CL) reaction. The light produced was then measured with a high-resolution CCD camera. These results showed that the MIP-based CL imaging can become a useful analytical tool for quick simultaneous detection of trans-resveratrol in a large number of real samples.Chapter 4 Molecularly imprinted polymer based on chemiluminescence imaging for the chiral recognition of Dns-phenylalanineA new molecularly imprinted polymer (MIP)-chemiluminescence (CL) imaging detection approach towards chiral recognition of Dns-phenylalanne (Phe) is presented. The polymer microspheres were synthesized using precipitation polymerization with Dns-L-Phe as template. Polymer microspheres were immobilized in microtiter plates (96 wells). The analyte was selectively adsorbed on the MIP microspheres. After washing, the bound fraction was quantified based on peroxyoxalate chemiluminescence (PO-CL) analysis. In the presence of Dns-Phe, bis(2, 4, 6-trichlorophenyl)oxalate (TCPO) reacted with hydrogen peroxide (H2O2) to emit chemiluminescence. The signal was detected and quantified with a highly sensitive cooled charge-coupled device (CCD). Influencing factors were investigated and optimized in detail. Control experiments using capillary electrophoresis showed that there was no significant difference between the proposed method and the control method at a confidence level of 95%. The method can perform 96 independent measurements simultaneously in 30 min and the limits of detection (LODs) for Dns-LPhe and Dns-D-Phe were 0.025μmol/L and 0.075μmol/L (3σ), respectively. The relative standard deviation (RSD) for 11 parallel measurements of Dns-L-Phe (0.78μmol/L) was 8%. The results show that MIP-based CL imaging can become a useful analytical technology for quick chiral recognition.Chapter 5 Chemiluminescence imaging assay dipyridamole based on molecular imprinted polymer as recognition materialA simple, sensitive and specific method has been developed for high throughput detection of dipyridamole. The proposed method is based on chemiluminescence (CL) imaging assay combined molecularly imprinted polymer (MIP) recognition. Polymer as the artificial biomimetic recognition element for dipyridamole was coated in 96- microtiter well plates with poly(vinyl alcohol) (PVA) as glue. The amount of polymer-bound dipyridamolewas determination based on dipyridamole peroxyoxalate chemiluminescence (PO-CL) reaction. The emitting light was measured with a high-resolution charge couple device (CCD) camera. Influencing factors were investigated and optimized in detail. The proposed method in this paper exhibits high selectivity and sensitivity to dipyridamole. Under the optimum conditions, the relative CL imaging intensity (AVG) is proportional to the concentration of dipyridamole ranging from 0.02 to 10μg/mL. The detection limit is 0.006μg/mL. The method can perform 96 independent measurements simultaneously in 30 min. These results show that the MIP-based CL imaging method can become a useful analytical technology for quick detection of dipyridamole in real sample.Chapter 6 Determination of rhodamine B in water by molecular imprinted polymer and CL imageingA simple, sensitive and specific method has been developed for high throughput detection of rhodamine B. Molecular imprinted polymer microspheres were prepared by precipitation polymerization. Polymer microspheres were immobilized in microtiter plates (96 wells). The analyte was selectively adsorbed on the MIP microspheres. After washing, the bound fraction was quantified based on peroxyoxalate chemiluminescence (PO-CL) analysis. The signal was detected and quantified with a highly sensitive cooled charge-coupled device (CCD). In addition, the developed method was satisfactorily applied to the determination of rhodamine B in water samples.Chapter 7 Determination of fluoranthene in water by molecular imprinted polymer and CL imageingFluoranthene is a representative compound among polycyclic aromatic hydrocarbons (PAHs). PAHs is a kind toxic organic contamination distributing in environment abroad and difficult to be degraded by biology, is a kind environmental carcinogens described earliest.oweing to the lower solubility in water and hydrophobicity, the detection of these compounds was very difficult. This work detected fluoranthene in the water by conbinding the high sensitivity CL imageing assay and high selectivity MIP. The results showed that MIP could be an enrichment technology.Part Two MIP-fluorescence optical fiber sensor assayChapter 1 The development of fiber optic sensorThis charpter reviewed the development of fiber optic sensor. It is containing the progress of fiber optic sensor in recent years, the mechanisms of fiber optic sensor, the methods of fixing sensitive materials and the trend of fiber optic sensor was described.Chapter 2 The study of oxidization fluorescence sensor with molecular imprinting polymer and its application for 6-Mercaptopurine (6-MP) determinationThis paper developed high-performance optical fiber sensors based on molecular imprinting polymer (MIP) and studied the application in 6-Mercaptopurine (6-MP) pharmaceutical formulations, human serum and urine samples. The sensors were fabricated by coupling the optical fibers with the polymer coated in 96-microtiter well plates using poly(vinyl alcohol) (PVA) as glue. The polymer acted as the artificial biomimetic recognition element for 6-MP. The MIP microspheres with uniform shape were prepared using precipitation polymerization method. During the determination, 6-MP was oxidized to a strong fluorescent compound with H2O2 in the alkaline media, which was one of the maim advantages that made it could be washed off easily from MIP and detected sensitively with fluorescence. This molecular imprinting approach offered a relatively nice selectivity for 6-MP detection. In addition, the developed method was satisfactorily applied to the determination of 6-MP in human serum samples.Chapter 3 The study of oxidization fluorescence sensors with molecular imprinting polymer and the application for carbamazepine determinationThis paper developed high-performance optical fiber fluorescence sensors based on molecular imprinting polymer (MIP). As a selective recognition material, the polymers were coupled with optical fiber fluorimetry detection for the efficient determination of carbamazepine (CBZ) in human serum. The sensors were fabricated by coupling the optical fiber fluorimetry with 96-microtiter well plates coated MIP. After adsorbed to MIP, the CBZ was detected by fiber fluorescence spectrophotometer after oxidation with lead dioxide in the media of sulfuric acid and methanol (V:V=3:1), which was one of the maim advantages that made it could be washed off easily from MIP and detected sensitively with fluorescence. This molecular imprinting approach offered a relatively nice selectivity for CBZ detection. The relative standard deviation (RSD) was 5% for a same sensor (n=5) when CBZ concentration was 0.01μg/mL in serum. In addition, the developed method was satisfactorily applied to the determination of CBZ in human serum samples without any necessity for sample treatment or time-consuming extraction steps prior to the analysis.Chapter 4 The study of oxidization fluorescence sensor with molecular imprinting polymer andits application for folic acid determinationFluorescence feber optic sensor combined with MIP was fabricated. Imprinted uniform microspheres againsted folic acid were synthesized by precipitation polymerization and were fixed to microtiter plates (96 wells). The selective of the sensor was inhenced based on the MIP recognition of template. And its application to the analysis of milk powder, value of RSD (n = 5) obtained was 3.5%.
Keywords/Search Tags:molecular imprinted polymer, chemiluminescence imaging, fluorescence optical fiber sensor
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