| This thesis is focused on the application of high performanc capillaryelectrophoresis, synthesis and application of electrochemiluminescence probe. We alsodo some work with the combination of capillary electrophoresis andelectrochemiluminescence detection. It consists of the following four sections.1. A miniaturized capillary electrophoresis with electrochemical detection (CE-ECD)system for the separation and determination of xylitol,sorbitol in three commercialsugar-free gums was developed. Factors influencing the separation and detectionprocesses were examined and optimized. These two analytes have been separatedwithin 10min at a separation voltage of 4 kV in 70 mmol/L NaOH running buffer.Highly linear response was obtained at the range of 5.0×10-5～10-2 mol/L and5.0×10-5～5.0×10-2 mol/L with the detection limits (S/N=3) of 5.0×10-6 mol/L and2.5×10-6 mol/L for xylitol and sorbitol, respectively (r>0.9997). The proposed methodwas successfully applied to determine the gum samples with the RSD and averagerecoveries of 3.68%,4.51% and 98.1 %,91.1% for xylitol and sorbitol, respectively ( n= 10) . 2. A novel Ru(bpy)2(dcbpy)NHS labeling/aptamer based biosensor combined with goldnanoparticles amplification for the determination of lysozyme withelectrochemiluminescence (ECL) method is presented. In this work, aptamer, ECLprobe, gold nanoparticles amplification and competition assay are the main protocolsemployed in ECL detection. Thanks to all those protocols used, an original biosensorcoupled with aptamer and Ru(bpy)2(dcbpy)NHS is prepared, high selectivity andsensitivity are the main advantages over other traditional Ru(bpy)32+ biosensors. All theelectrochemical impedance spectroscopy (EIS) and atomic force microscopy (AFM)characterization illustrate that this biosensor is fabricated successfully. Finally, thebiosensor was applied to displacement assay in different concentrations of lysozymesolution and a ultrasensitive ECL signal was obtained. The ECL intensity decreasedproportional to the lysozyme concentration over the range from 1.0×10-13 mol/L to1.0×10-8 mol/L with detection limit of 1.0×10-13 mol/L. This strategy for the aptasensoropens a rapid, selective and sensitive route for lysozyme and other potential proteindetections.3. A novel sensitive electrogenerated chemiluminescence (ECL) method for thedetection of Hg2+ based on deoxyribonucleic acid (DNA) hybridization was developed.A probe based on Ru(bpy)2(dcbpy) was synthesized in our laboratory and this probe wasapplied to label DNA and then this DNA-ester probe was fabricated on the surface ofgold electrodes to detect Hg2+ in the environment. We synthesized two kind of DNAprobes to determine Hg2+. A detection limit of 5.0×10-8 mol/L (S/N=3) was achieved.This Ru(bpy)2(dcbpy)NHS label system is a simple and sensitive method,which couldbe further expand the application of ECL in environment.4. The analysis of sarcosine is of clinical importance in characterizing prostate cancer development. In this paper a rapid and reliable determination method for sarcosine inhuman urine based on capillary electrophoresis-electrochemiluminescence detection isdescribed. The conditions affecting separation and detection were systematicallyinvestigated. Finally, End-column detection of sarcosine in 5 mM Ru(bpy)32+ solution atapplied voltage of 1.20 V and 10 s electrokinetic injection time at 10 kV was performed.Under these conditions, this method was validated for stability, precision, linearity andaccuracy. Excellent linearity was obtained in the range of 0.25×10-3 mol/L-10-5 mol/L.The R.S.D. values of ECL intensity and migration time were 3.41% and 1.43% for 10-4mol/L sarcosine, respectively. A detection limit of 5×10-6 mol/L (S/N=3) was achieved.The proposed method was applied satisfactorily to the determination of standardsarcosine in buffer within 10 min. Finally, this method was applied to determinesarcosine in real urine sample of normal people and cancer patients successfully. As weexpected, this strategy can be used as a potential diagnoses method for prostate cancer. |
PDF Full Text Request