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1.
[Bmim]PF6萃取环境样品中四环素类抗生素残留   总被引:1,自引:0,他引:1  
对用疏水性离子液体([Bmim]PF6)萃取分离四环素类抗生素和传统的有机溶剂进行比较,实验结果表明,离子液体不仅有比有机溶剂好的萃取效果,而且对人类及其生存环境没有污染,并用疏水性离子液体萃取分离环境样品中四环素类抗生素残留,用紫外分光光度法检测其残留量.该方法简便、快速,回收率高,精密度高.  相似文献   

2.
牛乳中四环素类兽药残留量的监测调查   总被引:1,自引:0,他引:1  
刘军  刘清  刘钰  谢伟 《甘肃科技纵横》2002,31(5):40-40,42
分批随机采集不同类型养殖场奶牛的鲜(生)乳样品,采用高效液相色谱法进行四环素兽药残留的分析监测。在135个牛乳样品中有35个含有其被测四环素类兽药成分,占被调查样品的25.93%,其中金霉素、土霉素和四环素的样检出率分别为8%、18%、14%,中位数值分别为591、311、327ug/L。表明奶牛养殖过程存在滥用四环素族抗生素类兽药的现象,从而造成鲜(生)乳中兽药残留情况较严重。  相似文献   

3.
电堆积毛细管电泳法检测食品中四环素类抗生素残留   总被引:1,自引:0,他引:1  
建立了一种采用电堆积方式在线富集的毛细管电泳检测牛奶、鸡蛋和蜂蜜中(包括四环素、土霉素、强力霉素在内)3种四环素类抗生素残留的方法.对影响富集倍数和分离的主要因素进行了优化.最佳运行缓冲液为20mmol/L的柠檬酸盐溶液,pH为2.5,分离电压20kV;进样量25kV×30s.在优化条件下,四环素、土霉素和强力霉素的富集倍数分别为86,54和54;检出限为1.7~2.1,1.8~2.2和1.9~2.2μg/kg;定量下限均为20μg/kg,仅为欧盟标准中最大残留限量的1/5(牛奶)和1/10(鸡蛋).方法可应用于鸡蛋、牛奶和蜂蜜中3种四环素类抗生素残留的检测.  相似文献   

4.
大理市米线和饵丝中甲醛及吊白块含量检测   总被引:2,自引:0,他引:2  
目的:检测大理市市售米线和饵丝中甲醛和吊白块含量。方法:采用乙酰丙酮法检测甲醛,盐酸副玫瑰苯胺法(GB/T5009.34—2003)检测二氧化硫;根据甲醛和亚硫酸氢钠(以二氧化硫计)含量及其比值判定吊白块的含量,并依据食品添加剂使用卫生标准(GB2760—1996)进行评价。结果:60份样品中,甲醛检出率100%,含量范围0.37~5.07mg/kg;二氧化硫检出率60%,含量范围0.14~11.88mg/kg;吊白块未检出。结论:本次检测样品中都没有添加吊白块,但可能存在违法违规使用甲醛和亚硫酸盐的情况,应加强监督检测。  相似文献   

5.
某市部分牛奶中抗生素残留情况的检测分析   总被引:1,自引:0,他引:1  
目的:了解某市部分牛奶中抗生素的残留情况,为安全饮用牛奶提供依据。方法:随机抽取品牌袋装及养殖户散装牛奶127份,其中样品1、2为品牌袋装牛奶,样品3、4为养殖户散装牛奶。用国标法(TTC法),按GB/T 4789.27-2003规定进行检测。结果:127份样品牛奶中,48份样品1:抗生素残留阳性数17份,阳性率35.4%。57份样品2:抗生素残留阳性数34份,阳性率59.6%。7份样品3和15份样品4,无抗生素检出。结论:品牌袋装牛奶中抗生素检测阳性率较高,养殖户散装牛奶未检出抗生素残留。食品卫生安全存在问题,应进一步加强食品卫生安全方面的监督及管理。  相似文献   

6.
水产品中恩诺沙星药物残留检测方法研究进展   总被引:2,自引:0,他引:2  
恩诺沙星属于喹诺酮类抗生素药物,具有广谱杀菌、耐药菌少等优点,被广泛用于水产养殖疾病的防治。该药物使用不当极易造成水产品中残留超标进而危害人体健康。主要从样品前处理技术和水产品中恩诺沙星残留检测方法两方面进行阐述,并对各种检测方法的特点进行分析讨论,以期为我国水产品中恩诺沙星残留的检测和监管提供参考。  相似文献   

7.
大理市市售腌菜中寄生虫卵的检测分析   总被引:1,自引:0,他引:1  
目的:了解大理市市售腌菜中寄生虫卵情况。方法:采用离心沉淀法检测腌菜中的寄生虫卵。结果:对100份样品进行检测,检出含有寄生虫卵的腌菜3份,检出率为3.0%。结论:大理市市售腌菜存在感染人的风险,应加强综合治理。  相似文献   

8.
目的:了解大理市散装食品包装纸中砷的含量。方法:采用银盐法分析散装食品包装纸中砷含量情况。结果:16份样品中,12份检出砷,检出率为75.0%,16份样品均未超过国家标准值,合格率为100%。通过对各大超市和散装点检出率及砷含量进行比较,检出率差异有统计学意义,而含量差异无统计学意义;对是否含有油墨两种样品中的检出率及砷含量进行比较,检出率差异有统计学意义,而含量差异无统计学意义。结论:本次所检测的散装食品包装纸的卫生状况还是比较好的,但其砷的检出率高,说明仍存在一些问题,卫生监督部门应该引起重视。  相似文献   

9.
近年来因农药的大量使用致使食品的农药残留问题备受关注,建立快速,灵敏,有效的农残检测技术是关注的焦点。农药残留检测中样品前处理技术是检测过程中耗时最长,最容易出现误差的步骤。样品前处理技术能提高农药残留检测的效率和准确率。本文综述了近年来食品中农药残留检测样品的前处理技术。  相似文献   

10.
目的:了解大理市销售的部分化妆品微生物污染情况,为群众使用化妆品提供意见。方法:对大理市市售的洁肤类和爽肤类10份化妆品进行了微生物学检测,检测方法按GB7918-87《化妆品微生物标准检测方法》进行,并按卫生部颁布的《化妆品卫生规范》进行检测结果分析评定。结果:共检测10份化妆品,不合格率为30%,主要是因菌落总数超标,在检测的样品中未检测出粪大肠菌群、绿脓杆菌、金黄色葡萄球菌。结论:大理市销售的化妆品卫生质量状况一般,少部分化妆品存在不同程度的微生物污染,建议加强对化妆品原材料和生产过程的卫生监控。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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