【作者】 唐玲丽；

【导师】 董元华； 刘德辉；

【作者基本信息】 南京农业大学 ， 生态学， 2009， 硕士

【摘要】 兽药对环境污染的研究越来越受到广泛重视,在许多土壤和水域中均发现了不同程度的抗生素残留。环丙氨嗪是一种高效的昆虫生长抑制剂类杀虫剂,广泛用于畜禽养殖业中作为饲料添加剂以控制动物厩舍内蝇蛆的生长发育。其代谢产物三聚氰胺是一种重要的化工原料,由于含氮量很高(66%),被广泛添加到饲料中用以“增加”产品的表观蛋白质含量。近年来环丙氨嗪和三聚氰胺在动物性食品中的残留问题十分严重,环丙氨嗪在水体、土壤及大气中均有检出,各国都对该药制定了严格的残留限量标准。动物口服的环丙氨嗪约99%以原药或代谢物三聚氰胺的形式通过畜禽粪便排泄的方式进入环境中,对环境造成潜在威胁。但迄今环丙氨嗪和三聚氰胺在我国主要类型耕地土壤中的环境行为数据仍为空白。本文在建立高效液相色谱法检测土壤中环丙氨嗪和三聚氰胺残留的基础上,研究了环丙氨嗪和三聚氰胺在江西红壤、江苏黄棕壤、太湖地区水稻土、河南潮土和黑龙江黑土中的吸附行为特征及其影响因素。首先,建立了土壤中环丙氨嗪和三聚氰胺残留的高效液相检测方法。方法采用Phenomenex Gemini C18色谱柱,以乙腈和pH=3.0的磷酸水溶液为流动相,梯度洗脱,流速为0.3ml／min,紫外检测波长为214nm,12min内可以测定环丙氨嗪和三聚氰胺在土壤中的残留量。土壤经(?)(NH40H)=5%的甲醇溶液提取浓缩后,环丙氨嗪和三聚氰胺土壤中的回收率分别为87.2～101.1%和75.3～101.6%,最低检测限分别为0.05mg／kg和0.07mg／kg。本方法操作快速、简单,易于普及,能够满足环丙氨嗪和三聚氰胺在土壤中残留检测的要求。其次,基于所建立的实验分析方法,采用批量平衡法,研究了环丙氨嗪和三聚氰胺在江西红壤、江苏黄棕壤、太湖地区水稻土、河南潮土和黑龙江黑土中的吸附特征。Freundlich模型和Langmuir模型均能较好地拟合吸附数据,拟合曲线均表现为良好的线性关系。结果表明：5种土壤对环丙氨嗪和三聚氰胺的吸附能力有所差异,其1gKf值分别在1.651～2.656、1.632～2.549之间。吸附常数Kf与土壤有机质含量呈显著正相关,与土壤pH之间呈显著负相关,而与土壤其他理化性质间相关性不明显。环丙氨嗪和三聚氰胺在5种供试土壤中的吸附自由能变化-△G为20.8～23.0kJ／mol,均小于40kJ／mol,表明其在这5种土壤中的吸附以物理吸附为主。此外,进一步研究了土壤pH、阳离子强度和柠檬酸对环丙氨嗪和三聚氰胺在土壤中吸附的影响。结果表明：环丙氨嗪和三聚氰胺在潮土中的线性吸附参数对数值1gKd随pH的变化趋势不明显,1gKd值在1.65左右；在其余4种供试土壤中,在试验pH范围(3～11)内,环丙氨嗪和三聚氰胺在4种土壤中的吸附参数对数值1gKd先随pH的增加逐渐降低,而当土壤溶液pH为碱性时,1gKd值随pH的增加无明显变化。环丙氨嗪和三聚氰胺在5种土壤中的吸附量随着离子强度的逐渐增强而减少,之后逐渐趋向于稳定。随着柠檬酸浓度的增加,环丙氨嗪和三聚氰胺在水稻土中的吸附量逐渐降低。这说明了柠檬酸对环丙氨嗪和三聚氰胺在水稻土中的吸附起着抑制作用。更多还原

【Abstract】 Recently, growing attention has been paid on environment pollution caused by veterinary medicines, because residues of potentially harmful pharmaceutical antibiotics have been found in soils and waters. Cyromazine is a highly effective insect growth inhibitor pesticide, widely used in livestock and poultry industry as feed additive to control the maggot growth in animal stalls. Melamine, the metabolite of cyromazine, is an important chemical raw material, and has been widely added into animal feed to "increase" the apparent protein content of products due to its high content of nitrogen (66%). In recent years, it has become a serious problem of cyromazine and melamine residues in animalized food. Cyromazine has been detected in water, soil and air, therefore strict residue limit standard is made in the world. Cyromazine feeding to animals enters into the environment in the form of the original drug (99%) or the metabolite melamine via livestock and poultry excretion, potentially threatening the environment. But till now, the environmental behavior data of cyromazine and melamine in the main types of soil in China was still in blank. In this paper, the adsorption characters and influence factors of cyromazine and melamine on five kind of soils(Ferrosols, Argosols, Anthrosols, Cambosols, Isohumosols)on the basis of determining cyromazine and melamine residues in soils by high-performance liquid chromatography(HPLC).Firstly, a new method for trace level analysis of cyromazine and melamine in soils by HPLC with gradient elution was presented in this paper. Phenomenex Gemini C18 column (150×4.60mm) was used and the mobile phase was a mixture of acetonitrile-orthophosphoric(pH=3.0) with a flow rate of 0.3mL/min. The residues of cyromazine and melamine in soils were detected at 214 nm of UV wave within 12 min. Soil samples were extracted and concentrated thrice by ultrasonic with cp (NH40H)= 5%methanol solution, then analyzed by HPLC. The average recovery rates of cyromazine and melamine were 87.2～101.1% and 75.3～101.6 respectively, with the detection limit of 0.05mg/kg and 0.07mg/kg respectively. This method is fast, easy and popular, and can meet the needs of detecting cyromazine and melamine residues in soils. Moreover, the adsorption characters of cyromazine and melamine in 5 kinds of soils were studied by batch equilibrium method on the basis of experimental analysis. Results showed that the experimental data are best described by the Freundlich and Langmuir model, while fitted successfully by the linear model. Different adsorption behaviors of Cyromazine and melamine are observed in the five tested soils,with the values of lgKfof cyromazine and melamine were 1.651-2.656 and 1.632-2.549 respectively. Adsorption constant (Kf) was significantly positively correlated with soil organic matter content (OM), while significantly negatively correlated with soil pH. In addition, the Kf had no apparent correlations with other physical and chemical soil properties. The adsorption free energy (-ΔG) of cyromazine and melamine in five kinds of soils changed in the range of 20.8 and 23.0 kJ/mol, smaller than 40kJ/mol. It indicated that in these soils, physical adsorption was the main form.Finally, the effects of the soil pH, cation intensity and citric acid on soil adsorption of cyromazine and melamine were studied. It showed that the logarithm values of linear adsorption parameter (lgKd) of cyromazine and melamine in Cambosols had no obvious change with the pH, and the value was about 1.65.At the tested pH interval of 3～11 of the rest of soil types, the lgKd gradually decreased with the increase of pH value, while it showed no apparent change concomitant with the pH when the soil solution was alkaline. The adsorption of cyromazine and melamine in five kinds of soils declined with the elevated cation intensity, and then gradually turned to be stable. With the increase in the concentration of citric acid, the paddy soil had a gradually reduced adsorption of cyromazine and melamine. This showed that citric acid inhibited the adsorption of cyromazine and melamine in the paddy soil.更多还原