Study On A Setup Of Capillary Electrophoresis With Miniaturized Fluorescence Detection System And Its Application

A simple, high sensitive, and low price capillary electrophoresis-laser induced fluorescence detection system(CE-LIF) has been designed. And the CE-LIF system was used to detect butyl rhodamine B and lissamine rhodamine B in food sample. The synthesis of molecularly imprinted solid-phase extraction(MISPE) monolithic column can be used for sample pretreatment methods of capillary electrophoresis, and removing impurity of sample to realize the trace analysis of samples. Meanwhile, the capillary electrophoresis detection range was greatly expended on account of the capillary electrophoresis indirect laser induce fluorescence detection. This paper includes the following five parts:1. The introduction was revealed in this section. Firstly, following the brief introduction of the capillary electrophoresis technology, the principle of CE-LIF system, the mainly used light source and optical path system at present, the way to improve the detection sensitivity were mainly introduced. Secondly, the principle and production methods of molecularly imprinted solid phase extraction, and its advantages in sample preparation were introduced in this paper. Finally, the advantage of the capillary electrophoresis with indirect laser induced fluorescence detection in enlarging the range of capillary electrophoresis detection was introduced, and summarized the research significance and purpose of this paper.2. A kind of simple, small volume, high sensitivity and low price of capillary electrophoresis- laser induced fluorescence detector was designed and produced. The excitation light source is laser diodes come from the laser pointers, the transmission-IVmedium of the excitation light is a Y-style optical fiber, and a four-branch optical fiber is used to collect the fluorescence in different directions in order to increase the fluorescence which have been collection. The collected fluorescence signals were converted to electrical signals though photomultiplier. The long wave pass filter was put in the front of photomultiplier to filter out the interference of stray light. The results show that the sensitivity of the detector is high. The detection limit for Rhodamine 6G is 7.7 nmol/L, and the optical path system design is novel. The advantages of this fluorescence detection system were compact, low volume, low-cost and could be combined with the microfluidic chip system.3. A high performance capillary electrophoresis-laser induced fluorescence detection method was established to separate and determine butyl rhodamine B and lissamine rhodamine B in chilli products. The effect of type, concentration and p H of electrophoretic medium, running voltage and sample size were investigated, and the best condition would be applied in the sample separation and determine. The results showed that butyl rhodamine B and lissamine rhodamine could be separated and determined effectively under the best condition, and the linear relationship about these two compounds was good in corresponding concentration range. The linear correlation coefficients were greater than 0.999, the average recoveries of standard addition was between 97.3% to 101.1 % and relative standard deviation was 2.5% to 3.7%.4. A molecularly imprinted solid-phase extraction coupled to capillary electrophoresis- laser induced fluorescence detection has been used to the detection of rose bengal in brown sugar. The rose bengal MISPE monolithic columns, which use rose bengal as imprinting molecule, methyl acrylamide(MAA) as functional monomer, ethylene glycol dimethyl methacrylate(EDMA) as cross-linker, azodiisobutyronitrile(AIBN) as initiator, were caused by hot in the capillary tube by in situ water-bath polymerization. The internal structure of molecularly imprinted polymer were characterized by scanning electron microscopy, and then the capacity and specificity of monolithic column column were tested combined with the CE- LIF system, and successfully applied to the enrichment and removing impurity of rose bengal in brown sugar sample finally. The results show that the recovery of the method was between 89.7 to 90.3%, the RSD was 3.6 % to 4.5 %, the detection limit(S/N = 3) was 9.0 ng/g, the column capacity was 1.314 μg/mg, and the enrichment factor was 63.5.5. A capillary electrophoresis-indirect laser induced fluorescence detection method, which used rhodamine B as fluorescence background material, has been used to the detection of neomycin in fish sample. In this way, neomycin with weak ultraviolet absorption can be detected effectively. The different kinds and concentration of background fluorescence material, different kinds and concentration of background buffer, p H, separation voltage which would effect on the result of separation and analysis were all studied in this experiment. Under the best conditions, the detection limit of neomycin was 10.0 ng/g, the recovery was between 95.2% to 99.7%, the RSD was between 2.7% and 3.6%.