【作者】 夏清海；

【导师】 杨亚玲；

【作者基本信息】 昆明理工大学 ， 环境生物学， 2014， 博士

【摘要】 随着人民生活水平和质量的提高,食品安全和环境污染问题越来越受到人们的关注。近年来,国内外因药物残留导致的食品安全和环境污染事件频频发生,药物在食品和环境中的残留问题已经成为人们关注的焦点。氟喹诺酮类抗生素作为人工合成的一类广谱抗菌药物,广泛应用于家禽水产等动物用于预防和治疗细菌感染。由于滥用、不合理使用以及不遵守休药期的规定,药物通过食物链进入人体或者环境中,从而对人类的健康及生存带来危害和威胁。因此,对其残留进行分析检测是非常必要的。药物的残留分析包括样品前处理和检测两个部分,样品前处理是残留分析中最为关键的步骤。到目前为止,关于氟喹诺酮类抗生素残留分析方法的研究大部分集中于检测技术的创新,而对于分析物的衍生化和样品前处理技术的研究较少。由于氟喹诺酮类抗生素在食品或环境中的残留量极低,开发出针对氟喹诺酮类抗生素在此类样品中的衍生化和前处理技术显得非常重要。本论文以氟喹诺酮类抗生素为研究对象,应用衍生化技术包括荷移反应、络合反应和包合作用增敏分析物荧光,样品前处理技术(双水相萃取、浊点萃取和超分子溶剂萃取)分离富集分析物,在重点解决衍生化和样品前处理等核心技术的基础上,结合分析仪器建立了快速灵敏、环保经济的氟喹诺酮类抗生素的分析新方法。本论文主要研究内容如下：(1)采用分子荧光光谱法研究了四种典型的氟喹诺酮类(FQs)抗生素包括诺氟沙星(NOR)、氧氟沙星(OFL)、环丙沙星(CIP)和加替沙星(GAT)与1,4二羟基蒽醌(1,4-DHAQ)的衍生化反应。通过FQs分子猝灭1,4-DHAQ的荧光,外标法定量,用分子荧光光度计检测环境水样中的FQs。在优化的实验条件下,四种FQs浓度在0.02～2.35μg/mL范围内与荧光强度呈现良好的线性关系,检出限为0.015～0.020μg/mL。在胶囊药剂样品和环境水样中加入已知浓度的标准分析物进行回收率实验,平均回收率为95.9～103.5%,相对标准偏差为0.7-2.5%。探讨了FQs分子猝灭1,4-DHAQ荧光的机理,测定了分子间衍生化反应的结合常数、结合位点以及自由能变化,确定了分子间结合的主要作用力为范德华力。(2)采用分子荧光光谱法研究了四种FQs (NOR, OFL, CIP, GAT)与2,3-二氯-5,6-二氰基对苯醌(DDQ)的衍生化反应及形成的衍生物荧光强度的变化,应用p-环糊精(p-CD)包合衍生物,考察了包合物的光谱性质和荧光强度。建立了p-CD包合FQs-DDQ衍生物,分子荧光光谱法检测蜂蜜中残留的FQs分析新方法。在优化的衍生化和包合条件下,四种FQs浓度在42.5～1340μg/kg范围内与荧光强度呈现良好的线性关系,检出限为11.6～15.4μg/kg在蜂蜜样品中加入已知浓度的标准分析物进行回收率实验,四种FQs的回收率为80.9～92.8%,相对标准偏差为1.6-4.0%。研究了FQs与DDQ衍生化反应的机理,测定了β-CD分子包合FQs-DDQ衍生物的包合比、包合常数。(3)采用分子荧光光谱法研究了四种FQs (NOR, OFL, CIP, GAT)和A13+之间的络合反应,结合盐析辅助液液超声萃取技术萃取FQs-A13+络合物。结果表明,A13+在pH4-5的水溶液中可与FQs形成稳定的具有强荧光的络合物,络合物在乙腈-硫酸铵双水相体系中被萃取富集到有机相中,用分子荧光光度计检测萃取物。建立了A13+衍生化-盐析辅助液液超声萃取-分子荧光光谱法检测牛奶中FQs的分析新方法。在优化的衍生和萃取条件下,四种FQs浓度在0.015～2.25μg/kg范围内与荧光强度呈现良好的线性关系,检出限为0.009～0.016μg/kg。在牛奶样品中加入已知浓度的标准分析物进行回收率实验,四种FQs的平均回收率为80.4-96.8%,相对标准偏差为0.5～2.5%。(4)研究了涡旋辅助酸诱导浊点萃取技术萃取环境水样中的四种FQs包括诺氟沙星、环丙沙星、沙拉沙星(SAR)和加替沙星,萃取物通过分子荧光光度计进行检测。建立了涡旋辅助酸诱导浊点萃取-分子荧光光谱法检测水样中FQs的分析新方法。在优化的萃取条件下,样品中四种FQs的浓度在0.045～0.90μg/kg范围内与其荧光强度呈现良好的线性关系,检出限为0.007～0.013μg/kg。在水样中加入已知浓度的标准分析物进行回收率实验,四种FQs的回收率为83.0～96.7%,相对标准偏差为0.9～3.7%。(5)研究了四种FQs (NOR, CIP, SAR, GAT)与4-氯-7-硝基苯-2-氧-1,3-二唑(NBD-C1)之间的衍生化反应,通过柱前衍生形成复合物结合超声辅助浊点萃取技术萃取FQs衍生物。建立了NBD-C1衍生化-浊点萃取-高效液相色谱法检测鸡蛋中FQs的分析新方法。实验优化了FQs衍生化和浊点萃取的条件,在优化的实验条件下,四种FQs通过Agilent TC-C,8(4.6×250mm,5μm)色谱柱在30min内得到完全分离,浓度在1.2～73.0μg/kg范围内与色谱峰面积呈现良好的线性关系,检出限为0.2～0.5μg/kg。在鸡蛋样品中加入已知浓度的标准分析物进行回收率实验,四种FQs的回收率为86.2～103.5%,相对标准偏差为0.6-4.3%。(6)研究了超分子溶剂萃取技术萃取奶粉中的四种FQs包括培氟沙星(PEF)、二氟沙星(DIF)、恩诺沙星(ENR)和达氟沙星(DAN),建立了壬酸-四丁基氢氧化铵超分子溶剂萃取-高效液相色谱法检测奶粉中FQs的分析新方法。实验优化了超分子溶剂萃取的条件,在优化的实验条件下,四种FQs的峰面积与浓度在10～1200μg/kg范围内呈现良好的线性关系,检出限为1.7～4.5μg/kg。在婴幼儿奶粉中加入已知浓度的标准分析物进行回收率实验,四种FQs的回收率为85.5-104.3%,相对标准偏差为0.9-3.9%。通过核磁共振光谱(’HNMR)探讨了超分子溶剂高效萃取FQs的机理,萃取的主要驱动力为分子间形成的氢键和疏水相互作用力。更多还原

【Abstract】 With the improvement of people’s living standards and quality, food safety and environmental pollution problem were getting people’s attention. In recent years, the incidents of food safety and environmental pollution occured frequently because of drug residues, which have become the focus of attention in food and the environment. Fluoroquinolones, as a class of synthetic broad-spectrum antimicrobial drugs, were widely used for the prevention and treatment of bacterial infections in poultry and aquatic animals. Owing to abuse, irrational use, and non-compliance with the withdrawal period, the drug entered into the human body or the environment through the food chain, and thus caused harm and threats to human health and survival. Therefore, it was very necessary for the analysis of drug residues in food and the environment.Analysis of drug residues consisted of two parts, sample pretreatment and determination, sample pretreatment was a more critical step in drug residue analysis. So far, analysis of fluoroquinolone residues was confined to developing new detection techniques, and less focused on study of derivatization and sample pretreatment techniques. In view of trace fluoroquinolones in food and the environment, it was very important for development of derivatization and pretreatment techniques in these samples. In this thesis, fluoroquinolones were selected as the research objects. The application of derivatization including charge transfer reaction, complexation reaction, and inclusion was to sensitize fluorescence of analytes, sample pretreatment techniques (aqueous two-phase extraction, cloud point extration, and supramolecular solvent extraction) were applied for separation and enrichment of the analytes. Focusing on solving core technology of derivatization and sample pretreatment, coupled with analytical instruments, rapid, sensitive, eco-friendly and economical methods were established for analysis of trace fluoroquinolones in samples.The main research contents of this thesis were as follows:(1) Derivatization of four typical fluoroquinolones (FQs) namely norfloxacin (NOR), ofloxacin (OFL), ciprofloxacin (CIP), and gatifloxacin (GAT) with1,4-dihydroxyanthraquinone (1,4-DHAQ) was studied by fluorescence spectroscopy. Through fluorescence quenching of1,4-DHAQ and quantitative analysis by external standard method, FQs were analyzed by fluorescence spectrometer in water samples. Under the optimum conditions, there was a good linear relationship between the fluorescence intensities of four FQs and the concentration in the range of0.02～2.35μg/mL, the detection limits varied from0.015to0.020μg/mL. The average recoveries were95.9-103.5%with the relative standard deviations from0.7to2.5%by adding standards of known concentration in pharmaceutical preparations and environmental water samples for recovery experiment. The mechanism of fluorescence quenching was discussed, binding constants, binding sites, and free energy changes were determined for intermolecular derivatization, it was figured out that the main binding force was Van der Waals force between molecules.(2) Derivatization of four FQs (NOR, OFL, CIP, GAT) with2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and fluorescence intensity of derivatives were studied by fluorescence spectroscopy. β-cyclodextrin (β-CD) was used for inclusion of derivatives, spectral property and fluorescence intensity of inclusion complex were investigated. A new method based on inclusion of FQs derivatives by β-CD coupled with fluorescence spectrometry for analysis of FQs in honey was established. Under the optimized conditions of derivatization and inclusion, a good linear relationship existed between the fluorescence intensities of four FQs and the concentration in the range of42.5-1340μg/kg, the limits of detection ranged from11.6to15.4μg/kg. By adding standards of known concentration in honey, the recoveries of four FQs between80.9%and92.8%were obtained, with the relative standard deviations in the range of1.6～4.0%. Derivatization mechanism of FQs with DDQ was studied, and inclusion ratio and inclusion constants were also determined.(3) Complexation reaction of FQs (NOR, OFL, CIP, GAT) with Al3+was studied by fluorescence spectroscopy, and salting-out assisted liquid-liquid ultrasonic extraction (SALLUE) was applied for extraction of FQs-Al3+complexes. The results showed that FQs and Al3+could form stable complexes with strong fluorescence in aqueous solution at pH4～5. Complexes were extracted into the organic phase through acetonitrile-ammonium sulfate aqueous two-phase system, and analyzed by spectrofluorometer. A new method based on Al+derivatization coupled with SALLUE, followed by fluorescence spectroscopy was established for analysis of FQs in milk. Under the optimized conditions of derivatization and extraction, there was a good linear relationship between the fluorescence intensities of four FQs and the concentration in the range of0.015～2.25μg/mL, the detection limits were in the range of0.009～0.016μg/mL. The average recoveries of four FQs between80.4%and96.8%were obtainded by adding standards of known concentration in milk, the relative standard deviations ranged from0.5to2.5%.(4) Vortex assisted acid-induced cloud point extraction (VAACPE) was studied for extraction of four FQs including NOR, CIP, SAR, and GAT in environmental water samples, the extracts were analyzed by spectrofluorometer. A new method based on VAACPE coupled with fluorescence spectroscopy was established for the determination of FQs in water samples. Under the optimum conditions, a good linear relationship was obtained between the fluorescence intensities of four FQs and the concentration in the range of0.045～0.90μg/mL, the limits of detection were in the range of0.007～0.013μg/mL. The average recoveries of four FQs ranged from83.0%to96.7%by adding standards of known concentration in water samples, and the relative standard deviations were in the ranged of0.9-3.7%.(5) Derivatization of four FQs (NOR, CIP, SAR, GAT) with4-chloro-7-nitrobenz-2-oxa-1,3-diazole (NBD-C1) was studied, FQs derivatives were formed through pre-column derivatization, and extracted by ultrasound-assisted cloud point extraction (UACPE). A new method based on NBD-C1derivatization coupled with UACPE and HPLC analysis was established for the determination of FQs in eggs. The conditions of derivatization and extraction were optimized, under the optimum conditions, four FQs were completely separated through Agilent TC-C18(4.6×250mm,5μm) column whitin30min. A good linear relationship presented between the peak areas of four FQs and the concentration in the range of1.2-73.0μg/kg, the limits of detection ranged from0.2to0.5μg/kg. The recoveries of four FQs varied from86.2%to103.5%, with the relative standard deviations of0.6～4.3%by adding standards of known concentration in egg samples.(6) Supramolecular solvent extraction (SMSE) of four FQs namely pefloxacin (PEF), difloxacin (DIF), enrofloxacin (ENR), and danofloxacin (DAN) was studied, a new method was established based on nonanoic acid (NoA)-tetrabutylammonium hydroxide (TBAH) supramolecular solvent extraction followed by HPLC-FLD analysis. The SMSE conditions were optimized, under the optimum conditions, there was a good linear relationship between the peak areas of four FQs and the concentration in the ranged of10～1200μ/kg, the limits of detection were1.7～4.5μg/kg. The recoveries of four FQs, investigated by adding standards of known concentration in infant formula, were in the range of85.5～104.3%, with the relative standard deviations of0.9-3.9%. The mechanism of SMSE for FQs was investigated by1H NMR, the main driving force of extraction was intermolecular hydrogen bonding and hydrophobic interaction between NoA and FQs.更多还原