Studies On The Active Ingredients In Citrus Reticulata Cv.Chachiensis And Poisonous Components In Solanum Tuberosum L By Using Molecular Imprinting Technique And Liquid Liquid Extraction

Because of the complexity of sample matrixes and low target levels of analytes in food and pharmaceutical analysis, an appropriate sample pre-treatment method is needed to separate and enrich the target analytes. The purpose of sample pre-treatment is to maximize the concentration of target compounds and to minimize the interference of impurities and matrix, which guarantees a high senstivity, accuracy and precision. Although the sample pre-treatment technologies are well advanced at present, more rapid, simple, effective and automatic sample pre-treatment methods are still needed. Traditional sample pre-treatment methods include liquid-liquid extraction and solid phase extraction. The major defect of traditional methods is lack of specific recognition. Molecular imprinting technique has the ability to overcome the drawbacks of these traditional sample pre-treatment methods.Therefore, this study developed a new sample pre-treatment technique molecularly imprinted solid phase extraction for the extraction and separation of hesperetin from the fresh of Citrus reticulata cv. Chachiensis. At the same time, the applications of traditional liquid-liquid extraction method for the analysis of poisonous components in potatoes were also investigated. This thesis was divided into four chapters. The main contents of each chapter were described as follows:In chapter one, various sample pre-treatment methods were summarized comprehensively. The history and the basic principle of molecular imprinting technique(MIT) were introduced specially. Moreover, the classification, the fabrication methods and the applications of molecularly imprinted polymers(MIP) were concluded systematically.Finally, the objectives and significances of this research were highlighted.In Chapter two, a hesperetin based molecularly imprinted monolithic column was fabricated through an in-situ co-polymerization method using hesperetin as the template,acrylamide(AM) as the functional monomer, ethylene glycol dimethacrylamide(EGDMA)as the cross-linker and a mixed solvent of methanol, toluene and dodecanol as porogen. The molar ratio of template molecular, functional monomer and crosslinker was carefully optimized. In addition, different kinds and proportions of porogen were investigated to obtain the best synthesis condition for hesperetin MIP. The results showed that the optimal molar ratio of template : functional monomer : crosslinker was 1 : 2 : 40 and the porogen mixture was consisted of methanol, toluene and dodecanol. The optimal content of toluene in the mixed porogen was 20%(v/v). Fourier transform infrared(FT-IR) spectroscopy,scanning electron microscopy(SEM) and selective experiment were carried out to characterize hesperetin MIP. The experimental results showed that hesperetin based MIP was prepared successfully, and the hesperetin molecularly imprinted monolithic column exhibited a high selectivity for hesperetin. Hesperetin molecularly imprinted monolithic column was used for the extraction and purification of hesperetin from the flesh of Citrus reticulata cv. Chachiensis. High performance liquid chromatography(HPLC) was adopted to determine the contents of hesperitin. The recovery of hesperetin was ranged from 87.6%to 94.0%(n = 3). The above results showed that this MIP monolithic column had a good recognition performance for hesperetin and had a wide application prospect in extracting and purifying hesperetin from the flesh of Citrus reticulata cv. Chachiensis.In Chapter three, a new method was developed for the determination of α-solanine in potatoes using liquid-liquid extraction and high performance liquid chromatography(HPLC). In this method, acetic acid was used to extract α-solanine in potatoes. Theα-solanine extracts was partitioned with water saturated isobutyl alcohol. The determination of α-solanine was conducted using HPLC. The separation was conducted on a reversed-phase Discovery C18 column(150 mm × 4.6 mm, 5 μm). The mobile phase was consisted of acetonitrile-0.02 mol/L potassium dihydrogen phosphate(22 : 78, v/v) and the flow rate was 1.0 mL/min. The detection wavelength and the column temperature were setat 210 nm and 30 oC, respectively. There was a good linear relationship between the peak area and the concentration of α-solanine within 0.02-1.00 mg/mL(r = 0.9997). The limit of detection(S/N = 3) and the limit of quantification(S/N = 10) were 0.68 and 2.27 μg/mL respectively. The recoveries of different levels were between 98.0% and 116.0%. The relative standard deviation(RSD) of precision was ranged from 0.16% to 1.79%. The method was simple, fast, precise, and it was suitable for rapid determination of α-solanine in potatoes.In chapter four, the conclusions and prospects of this research were described.