【作者】 汤凯洁；

【导师】 汤坚；

【作者基本信息】 江南大学 ， 食品营养与安全， 2009， 博士

【摘要】 磺酰脲类除草剂具有高效性、广谱性、低毒性等优点,目前已成为使用最广泛的除草剂之一,我国常用的磺酰脲类除草剂包括21个品种,它们被用于水稻、麦类、油菜、大豆、玉米等多种作物中防除杂草。随着该类除草剂使用量及使用范围的不断加大,其在农作物中的残留、对环境的污染及对人类健康造成的危害也越来越为人们所重视。欧盟制定了磺酰脲类除草剂在饮用水中的限量标准,日本、美国和欧盟等发达国家对国际贸易农产品中的磺酰脲类除草剂也分别制定了限量标准。该类除草剂由于残留量低,样品成份复杂,样品的预处理已成为制约该类除草剂分析检测的瓶颈技术。本论文建立了苄嘧磺隆、甲磺隆,苯磺隆和烟嘧磺隆的HPLC和HPLC-MS检测方法,并以苄嘧磺隆为模板分子合成了苄嘧磺隆分子印迹聚合物,以该聚合物为填料,制备了对苄嘧磺隆具有选择性的分子印迹固相萃取柱（MISPE）,应用该柱对大豆、大米、面粉和玉米粉等样品中磺酰脲类除草剂进行富集和净化预处理,采用HPLC和LC-ESI-MS方法检测。具体研究结果如下:建立了苄嘧磺隆（BSM）、甲磺隆（MSM）、苯磺隆（TBM）和烟嘧磺隆（NS）的HPLC分离检测方法,四种磺酰脲类除草剂在0.1-7μg.mL^-1浓度范围线性关系良好,相关系数在0.9997-0.9999之间。分别对大豆和大米样品进行了加标回收率试验,加标样品中BSM、MSM、NS和TBM的回收率在68.9-85.6 %。建立了LC-ESI-MS对NS、MSM、TBM和BSM等几种磺酰脲类除草剂的分析方法,其中质谱分离条件为:采用正离子检测模式,检测质量范围为m/z 200～800 u,毛细管电压3.93 kV,锥孔电压20 V,脱溶剂温度250 oC,真空度2.6×10-5 mBar,辅助气流速4 L/h。NS、MSM、TBM和BSM在0.01-0.7μg.mL^-1浓度范围内线性良好,相关系数TBM的R2为0.9999,而BSM, MSM和NS的R2均为1。根据已确定的LC-ESI-MS分析方法进行了大米和大豆的回收率测定,大豆的回收率在68.4～88.1 %,大米的回收率在72.7～88.6 %。采用Hyperchem 7.0软件计算方法、紫外扫描及核磁共振技术为BSM筛选了最佳的功能单体为甲基丙烯酸（MAA）。以BSM为模板分子,MAA为功能单体,TRIM为交联剂,二氯甲烷为致孔剂,通过单因素试验和响应面优化确定了MIP合成工艺条件:以二氯甲烷致孔剂为35.14 mL,T/F为0.24,F/C为0.547,此条件下合成的MIP对BSM的理论吸附值（Q）为130.79μmol.g^-1,而实测MIP吸附量（Q）为129.52μmol.g^-1。在此工艺条件下紫外引发制备的MIP4的吸附容量(128.6μmol.g^-1)高于加热引发制备的MIP3(35.8μmol.g^-1);以DVB:TRIM(1:1, mol.L^-1)为交联剂制备的MIP5比单独以TRIM为交联剂制备的MIP4颗粒度更均匀,且吸附容量(145.3μmol.g^-1)高于MIP4 (128.6μmol.g^-1),但MIP5对BSM的选择性不如MIP4,原因可能是交联剂DVB结构中的苯环能与BSM、MSM、NS和TBM等分子结构中的苯环形成π-π结合,导致MIP5的选择性下降。从MIP4和MIP5对BSM、MSM、NS和TBM竞争性吸附实验可以看出,MIP中的印迹空穴能否与被吸附的分子形成双氢键相互作用位点,对MIP的吸附来说起着主导作用,而这四种结构类似物非作用位点的空间结构对印迹聚合物的识别起着非主导作用。以苄嘧磺隆为模板,MAA为功能单体,TRIM:DVB(1:1, mol.L^-1 )为交联剂,二氯甲烷20 mL为致孔剂合成了MIP,以该MIP为固相吸附填料制备了苄嘧磺隆分子印迹固相萃取柱,对该柱的洗脱程序进行了优化,结果为以二氯甲烷为上样溶剂,最大上样体积为25 mL,淋洗溶剂以乙腈-丙酮（1:2, v/v）,洗脱溶剂以甲醇-水（8:2, v/v）,2×2.5 mL洗脱率最高,对BSM的回收率达99.4 %。建立了MISPE-HPLC方法对加标大米和大豆样品中的BSM, MSM, NS和TBM进行测定,结果表明MISPE柱对BSM的回收率达98.8-100.6 %,高于ENVITM18-SPE柱,MSM和NS的回收率也高于ENVITM18-SPE柱,而TBM的回收率低于ENVITM18-SPE柱,该结果提示了采用该方法合成的MIP对BSM, MSM和NS的识别优于TBM,能用于大豆和大米实际样品的净化和富集预处理。更多还原

【Abstract】 Sulfonyrea is one of the most widely used herbicide because of its high herbicidal activity, broad-spectrum and low toxicity. Sulfonyreas have over 20 species in our country which are usually applied in different areas such as rice, oat, rape, soybean, maize and other types of fields. With the increasing using amount of sulfonyrea herbicides, people focus more attention on the residues in foods, environmental pollution and health hazard. The EU has defined a minimum required performance limits （MRPLs） for sulfonyrea herbicide in drinking water. Japan, USA and EU have defined the MRPLs for sulfonyrea herbicides in the agriculture products in international trade. Pretreatment become the bottle neck of analysis of sulfonyreas because the residues are very low and the sample matrixs are very complex. We have established the methodology of bensulfuron-methyl （BSM）, （metsulfuron-methy ） MSM, （nicosulfuron） NS and （tribenuron-methyl）TBM with HPLC and HPLC-MS. A molecularly imprinted polymer （MIP） was prepared with BSM as template molecule and the molecularly imprinted solid phase extract （MISPE） was made using the MIP as sorbent which can selectivity to BSM. A pretreatment methodology based on the MISPE procedure was developed for the determination of BSM, MSM, NS and TBM in the soybean samples and rice samples using HPLC and HPLC-ESI-MS. The study results as follow:The methodology of analysis of herbicides, such as BSM, MSM, NS and TBM was developed using HPLC. This analysis was suitable for BSM, MSM, NS and TBM, the calibration curves were linear in the concentration range from 0.1-7μg.mL^-1and the correlation coefficients were well between 0.9997-0.9999. The recoveries were between 70.3-85.6 % in rice sample. The methodology of analysis BSM, MSM, NS and TBM were developed using HPLC-ESI-MS. The MS conditions were as follows: in the positive ionization mode, detecting mass between 200-800 u, capillary voltage 3.93 kV, zone voltage 20 V, drying gas temperature 250 oC, the vaccum 2.6×10-5 mBar, gas flow 4 L/h, the calibration curves were linear in the concentration range from 0.01-0.7μg.mL^-1and the correlation coefficients were well between 0.9999-1. The recoveries were between 68.4-88.1 % in the soybean sample and 72.7～88.6 % in the rice samples based on the HPLC-ESI-MS.The soft of Hyperchem 7.0, UV scan and 1H NMR were used to choice the suitable functional monomer of BSM. Optimization for preparation MIP was achieved using the response surface analysis after single-factors test.The results as follow: porogen is 35.14 mL, the ratio of template molecular to function monomer is 0.24, the ratio of function monomer to cross-linker is 0.547. The maximum adsorptions of MIP to BSM are 130.79μmol.g^-1 by predicting of response surface analysis, and the actual adsorptions are 129.52μmol.g^-1. The adsorption (128.6μmol.g^-1) of MIP4 initiated by UV was higher than the adsorption (35.8μmol.g^-1) of MIP3 initiated by bath heat（60 oC）, which both were prepared using the BSM as template molecule, the MAA as functional monomer, TRIM as the cross-linker, dichloromethane as porogen. The particle size of MIP5 prepared using DVB: TRIM (1:1, mol.L^-1 ) as cross-linker more uniformly than MIP4 prepared using only TRIM as cross-linker, and the adsorption (145.3μmol.g^-1) of MIP5 higher than the adsorption (128.6μmol.g^-1) of MIP4. But the selectivity to BSM of MIP5 were low than MIP4. The reason maybe the structure of DVB can provideπ-πinteractions with the phenyl of BSM, MSM, NS, and TBM. It is important interactions that the double hydrogen bonds of complementary functional groups in the polymer with the template exhibited by the selective study of MIP4 and MIP5. However the shape-selective of four templates with cavity of MIP is less important.The MISPE cartridge was prepared using the MIP as the sorbent. The MIP was prepared using the BSM as template molecule, TRIM: DVB (1:1, mol.L^-1) as the cross-linker, dichloromethane （20 mL） as porogen. The MISPE extraction procedure has been optimized. The maximum recoveries of BSM were achieved when 25 mL dichloromethane as percolation solvent, washing solvent is acetonitrile-acetone （1:2, v/v）, elution solvent is methanol-water （8:2, v/v）. The recoveries of BSM are 99.4 %.The methodology of analysis BSM, MSM, NS and TBM was developed using MISPE-HPLC. The recoveries of BSM using MIP are up to 98.8-100.6 % which higher than ENVITM18-SPE cartridge, and the MSM and NS is higher than ENVITM18-SPE cartridge, too. But the recoveries of TBM are lower than ENVITM18-SPE cartridge. The results of recoveries demonstrate the MIP has the excellent recognition to BSM, MSM and NS than TBM. So this work demonstrates that the MIP can be used successful as adsorbent materials for SPE in soybean and rice samples purification and enrichment.更多还原