The Molecularly Imprinted Electrochemiluminescence Sensor And Its Application In Drug Detection

The spread of drugs has become a public hazard worldwide. The drug abuse has been the cause for the death of about 20 million people each year, millions of people loss the labor force, and the social development and stability was also seriously damaged. The detection of hidden drugs in luggage, mail, vehicles, and aircrafts, as well as in the human body is a great challenge to analysts, as this requires highly sensitive, specific, and fast methods for its solution. Electrochemiluminescence (ECL) detection can be a good candidate for such application, as it has simple optical setup, low-background disturbance, and very high sensitivity. On the hand, molecular imprinting technology (MIP) is able to provide the specificity for an analytical method. Such combination would be able to produce a sensor with both high sensitivity and a desirable selectivity. The main results of the thesis were given as follows:1. Based on the incorporation of electrochemiluminescence detection and the molecularly imprinted recognition strategy, a highly sensitive and selective sensor for the methamphetamine (MA) determination was reported. The sensor was fabricated by re-modification of the Ru(bpy)₃²⁺/Nafion/MWCNT electrode with a thin film of molecularly imprinted sol-gel polymers with specific binding sites for MA. The as-prepared sensor exhibited a very high sensitivity and excellent selectivity to the target molecule. A detection limit as low as 1.0×10^-15 mol/L was achieved with a linear range from 1.0×10-9 1.0×10-12 mol/L. The high sensitivity and selectivity of the sensor allowed detection of the presence of the MA drug, even in a closed container, by sampling its odor.2. A novel ECL-MIP sensor for determination of morphine was prepared. The sensor fabrication was divided into two steps. The first step is to coat Ru(bpy)₃²⁺ on the GC electrode based on MWCNTs/Titania/Nafion film and the second step involves the covering of an MIP layer on top of the first layer based on sol-gel technology. The sensor exhibited both high sensitivity and a desirable selectivity for morphine molecule detection in solution, and a detection limit of 2.0×10^-10 mol/L with a linear range of 1.0×10^-6 1.0×10^-9 mol/L. The sensor has good stability and regeneration capacity, being expected to become a new method for morphine detecion sensitively, rapidly, high selectivity.3. The electrochemistry and ECL behavior of a novel iridium complex (ppy)₂Ir(N-phBA) (ppy = 2-phenylpyridine, N-phBA = N-phenylbenzamide) was investigated in acetonitrile solution in the presence of tri-n-propylamine as a coreactant. Multi-wall carbon nanotubes/iridium(III) (MWNTs/Ir(III)) modified electrode was prepared, and the ECL property of sensor was studied. The new iridium(III) complex was found to display good sensitivity and low background light. The MWNTs/Ir(III) modified electrode can fabricated easily and can produce steady ECL in continuous Cyclic voltammetries scanning. These results provided information for others iridium(III) complexes ECL study and an efficient ECL system for analytical applications.