检索结果-南通市图书馆

Determination of Rotenone Residues in Foodstuffs by Solid-Phase Extraction (SPE) and Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS)

引用

Agricultural Sciences in China 2010年第9期9卷 1299-1308页

作者： XU Dun-ming ZHOU Yu LIN Li-yi ZHANG Zhi-gang ZHANG Jin LU Sheng-yu YANG Fang HUANG Peng-ying xiamen entry-exit inspection and quarantine bureau Xiamen 361026 P.R. China Fujian entry-exit inspection and quarantine bureau Fuzhou 350001 P.R.China

We developed a novel approach to determine rotenone residues in foodstuffs, by integrating solid-phase extraction （SPE） and liquid chromatography/tandem mass spectrometry （LC-MS/MS） technologies, to achieve high sensitivity and selectivity. In our method, the solvent extraction with n-hexane-dichloromethane （50：50, v/v） and cleanup with florisil SPE cartridges using ethyl acetate-ethyl ether （25：75, v/v） as eluents provided adequate recovery of rotenone. The detection of rotenone was then carried out by LC-MS/MS using acetonitrile-water with the 0.1% formic acid （w/v） as the mobile phase. The multiple reaction monitoring （MRM） scheme employed in the approach involved the transitions of the precursor ion to three selected product ions, in which one pair for quantification was m/z 395.3 〉 213.2 and the other two pairs for identification were m/z 395.3 〉 192.2 and 395.3 〉 367.0. The limits of quantification （LOQs） of the method ranged from 0.001 to 0.005 mg kg-1 depending on the matrix. Intra- and inter-day precisions （relative standard deviations, RSDs） for rotenone were less than 7.1 and 14.8%, respectively. Results from repetitive analysis suggested good reproducibility of the method for rotenone residue detection. The recoveries at three concentrations （LOQ, 10LOQ and 100LOQ） ranged from 79.3-118.3% in cabbage, potato, onion, carrot, apple, orange, banana, lichee, tea, and Shiitake mushroom. The proposed procedure was then applied to the analysis of 129 real samples collected from xiamen, Fujian Province, China. The existence of rotenone was found in two tea products with concentrations of 0.012 and 0.016 mg kg-1, respectively. The method has great potential for routine analysis of monitoring rotenone residue in foodstuffs.

关键词： rotenone LC-MS/MS foodstuff residue SPE

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Preparation of hydrophilic molecularly imprinted polymers for tetracycline antibiotics recognition

引用

Chinese Chemical Letters 2011年第5期22卷 611-614页

作者： Peng Wang Xiao Fang Fu Jing Li, Jing Luo Xiao Ya Zhao Ming Jun Sun Yin Zhu Shang Cheng Ye Hubei entry-exit inspection and quarantine bureau of PRC Wuhan 430022 China

Hydrophilic molecularly imprinted polymers（MIPs） were prepared using tetracycline as template,methacrylic acid as monomer and glycidilmethacrylate as pro-hydrophilic *** with common MIPs,the imprinting effect and adsorption amounts of hydrophilic MIPs for tetracycline（TC） were greatly improved in water ***,the electrochemical sensor fabricated by modifying hydrophilic MIPs on glassy carbon electrode was developed for the determination of TC in foodstuff samples.

关键词： Hydrophilic molecularly imprinted polymers Electrochemical sensor Tetracycline antibiotics Foodstuff samples

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Synthesis, Characterization and Crystal Structure of (+)-N-[(3S)-3-(4- fluorophenyl)heptanoyl]bornane-10,2-sultam

引用

Chinese Journal of Structural Chemistry 2012年第9期31卷 1247-1250页

作者：韩勰汪淼李菲徐媛原曹秀芳 College of Science Huazhong Agricultural University inspection and quarantine Technology Center Hainan Entry-exit Inspection and Quarantine Bureau

The chiral molecule （＋）-N-[（3S）-3-（4-fluorophenyl）heptanoyl]bornane-10,2-sultam （C23H32FNO3S, Mr = 421.56）, a fluorine-containing derivative of camphorsultam, was conveniently obtained and crystallized in the orthorhombic space group P212121 with a = 7.9044（11）, b = 11.6680（16）, c = 24.899（3） , V = 2296.4（5） 3, Z = 4, Dc = 1.219 Mg/m3, λ = 0.71073 , μ（MoKα） = 0.172 mm-1 and F（000） = 904. X-ray diffraction analysis reveals that the six-membered ring of sultam shows a boat conformation （Fig. 1）. The planes constructed by （（C6）, （C7）, （C8）, （C9）） and （（C4）, （C5）, （C6）, （C9）） form a dihedral angle of 70.3（3）°. The plane of （C1）-（C2）-（C3） forms dihedral angles to the aforementioned planes of 85.9（4） and 89.5（4）°, respectively. The molecules are linked via C-H···O/F interactions.

关键词： (+)-N- [(3S)-3-(4-fluorophenyl)heptanoyl] bornane-10,2-sultam,synthesis crystal structure

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Determination of Tetracyclines in Honey Using Liquid Chromatography with Ultraviolet Absorbance Detection and Residue Confirmation by Mass Spectrometry

引用

Chinese Journal of Chemistry 2007年第9期25卷 1294-1299页

作者：刘艳徐锦忠丁涛李公海 Food Laboratory Jiangsu Entry-Exit Inspection and Quarantine Bureau Nanjing Jiangsu 210001 China

A determination method has been optimized and validated for the simultaneous analysis of tetracycline （TC）, oxytetracycline （OTC）, chlortetracycline （CTC） and doxycycline （DC） in honey. Tetracyclines （TCs） were removed from honey samples by chelation with metal ions bound to small Chelating Sepharose Fast Flow columns and eluted with Na2EDTA-Mcllvaine pH 4.0 buffers. Extracts were further cleaned up by Oasis HLB solid-phase extraction （SPE）, while other solid-phase extraction cartridges were compared. Chromatographic separation was achieved using a polar end-capped C 18 column with an isocratic mobile phase consisting of oxalic acid, acetonitrile and methanol. LC with ultraviolet absorbance at 355 nm resulted in the quantitation of all four tetracycline residues from honey samples fortified at 15, 50, and 100 ng/g, with liner ranges for tetracyclines of 0.05 to 2 μg/mL. Mean recoveries for tetracyclines were greater than 50% with R.S.D. values less than 10% （n= 18）. Detection limits of 5, 5, 10, 10 ng/g for oxytetracycline, tetracycline, chlortetracycline and doxycycline, respectively and quantitation limits of 15 ng/g for all the four tetracyclines were determined. Direct confirmation of the four residues in honey （2-50 ng/g） was realized by liquid chromatography-tandem mass spectrometry （LC/MS/MS）. The linear ranges of tetracyclines determined by LC/MS/MS were between 5 to 300 ng/mL, with the linear correlation coefficient r〉 0.995. The limits of detection of 1 to 2 ng/g were obtained for the analysis of the TCs in honey.

关键词： tetracyclines honey metal chelate affinity chromatography LC/MS/MS

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Liquid-liquid Microextraction Based on Solidification of Floating Organic Drops Coupled with Gas Chromatography for Analyzing Trace Benzene, Toluene and Xylene in Water Samples

引用

Chemical Research in Chinese Universities 2011年第6期27卷 939-943页

作者： ZHANG Mao-sheng HUANG Jia-rong ZHENG Xiang-hua XIE Qiong-fang Department of Chemistry and Environmental Science Zhangzhou Normal University Zhangzhou 363000 P. R. China Zhangzhou entry-exit inspection and quarantine bureau Zhangzhou 363000 P. R. China inspection and quarantine Technical Center Xiamen Entry-Exit Inspection and Quarantine Bureau Xiamen 361012 P. R. China

A new liquid-liquid microextraction method based on the solidification of floating organic drops coupled with gas chromatography was developed for the determination of trace benzene, toluene and xylene（BTX） in water samples. In the microextraction procedure, a microdrop of n-decanol was delivered to the surface of the analytes’ solution, and stirred for a desired time. Following the absolute extraction, the sample vial was cooled in an ice bath for 10 min. The solidified n-decanol was then transferred into a plastic tube and melted naturally; and 1 μL of it was injected into gas chromatography for analysis. Factors relevant to the extraction efficiency were studied and optimized. The optimal experimental conditions were： 15 μL of n-decanol as extractive solvent, 30 mL of solution containing analytes, no salt, the stirring rate 400 r/min, the extraction temperature 30 °C, and the extraction time 30 min. Under those optimized conditions, the detection limit（LOD） of analytes was in a range of 0.05―0.10 ng/mL by the developed method. A good linearity（r0.99） in a calibration range of 0.01―100 μg/mL was obtained. The recoveries of the real samples at different spiked levels of BTX were in the range from 92.2% to 103.4%.

关键词： Gas chromatography Liquid-liquid microextraction Solidified floating organic drop n-Decanol

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Diatom diet selectivity by early post-larval abalone Haliotis diversicolor supertexta under hatchery conditions

引用

Chinese Journal of Oceanology and Limnology 2010年第6期28卷 1187-1194页

作者：张玉宇高亚辉梁君荣陈长平赵东海李雪松李扬吴文忠 Key Laboratory of Ministry of Education for Coast and Wetland Ecosystems and School of Life Sciences Xiamen University Dongshan entry-exit inspection and quarantine bureau

Benthic diatoms constitute the primary diet of abalone during their early stages of development. To evaluate the dietary preferences of early post-larval abalone, Haliotis diversicolor supertexta, we analyzed the gut contents of post-larvae that settled on diatom films. We compared the abundance and species diversity of diatom assemblages in the gut to those of the epiphytic diatom assemblages on the attachment films, and identified 40 benthic diatom species in the gut contents of post-larvae 12 to 24 d after settlement. The most abtmdant taxa in the gut contents were Navicula spp., Amphora copulate, and Amphora coffeaeformis. Navicula spp. accounted for 64.0% of the cell density. In the attachment films, we identified 110 diatom species belonging to 38 genera. Pennate diatoms were the dominant members including the species Amphiprora alata, Cocconeis placentula var. euglypta, Cylindrotheca closterium, Navicula sp. 2, and A. coffeaeformis. Nano-diatoms （〈20 pm in length） accounted for a considerable proportion of the total species number and cell density of the diatom assemblages in the gut contents and on the films. This suggests that nano-diatoms are important to the efficient production of abalone seed. The difference of the composition and abundance of diatoms between in the guts and on the biofilms suggests that early post-larval grazing was selective. An early post-larval abalone preferred nano-diatoms and the genera Navicula and Amphora during the month after settlement.

关键词： benthic diatoms feeding Haliotis diversicolor supertexta post-larval abalone

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

In vitro Selection of DNA Aptamers and Fluorescence-Based Recognition for Rapid Detection Listeria monocytogenes

引用

Journal of Integrative Agriculture 2014年第5期13卷 1121-1129页

作者： LIU Guo-qing LIAN Ying-qi GAO Chao YU Xiao-feng ZHU Ming ZONG Kai CHEN Xue-jiao YAN Yi School of Biotechnology and Food Engineering Hefei University of Technology Anhui entry-exit inspection and quarantine bureau

Aptamers are specific nucleic acid sequences that can bind to a wide range of nucleic acid and non-nucleic acid targets with high affinity and specificity. Nucleic acid aptamers are selected in vitro from single stranded DNA or RNA ligands containing random sequences of up to a few hundred nucleotides. Systematic evolution of ligands by exponential enrichment （SELEX） was used to select and PCR amplify DNA sequences （aptamers） capable of binding to and detecting Listeria monocytogenes, one of the major food-borne pathogens. A simplified affinity separation approach was employed, in which L. monocytogenes in exponential （log） phase of growth was used as the separation target. A fluorescently-labeled aptamer assay scheme was devised for detecting L. monoeytogenes. This report described a novel approach to the detection of L. monocytogenes using DNA aptamers. Aptamers were developed by nine rounds of SELEX. A high affinity aptamer was successfully selected from the initial random DNA pool, and its secondary structure was also investigated. One of aptamers named e01 with the highest affinity was further tested in aptamer-peroxidase and aptamer-fluorescence staining protocols. This study has proved the principle that the whole-cell SELEX could be a promising technique to design aptamer-based molecular probes for dectection of pathogenic microorganisms without tedious isolation and purification of complex markers or targets.

关键词： aptamers systematic evolution of ligands by exponential enrichment (SELEX) Listeria monocytogenes,rapid detection

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Prediction of the Shearing Property of Worsted Fabrics Using BP Neural Network

引用

Journal of Donghua University(English Edition) 2006年第6期23卷 47-49页

作者：徐广标张向华王府梅 College of Textiles Donghua University Panyu entry-exit inspection and quarantine bureau

In this paper, three layers of BP neural network were used to model the shearing properties of worsted fabrics. We train the neural network models with 27 kinds of fabrics, and then use 6 kinds of fabrics to validate ... 详细信息

关键词： worsted fabric shearing properties neural network models predictive accuracy.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The Technology Parameters Optimization of Extracting Natural Cellulose Fibers from Eulaliopsis Binata

引用

Journal of Donghua University(English Edition) 2010年第4期27卷 516-521页

作者：曲丽君郭肖青由瑞华孙亚宁迟德玲 College of Textile and Clothing Qingdao University Shandong entry-exit inspection and quarantine bureau

The extracting process and parameters optimization of Eulaliopsis binata fibers were *** components of Eulaliopsis binata were tested,the cellulose contents was about 45%,and the lignin content was as high as 18.5%.And the components of Eulaliopsis binata fibers were compared with some bast *** analysis of physical and chemical properties related to acid,alkali,and auxiliary agent about cellulose and pectin,and lignin components in Eulaliopsis binata fibers were *** chemical processing was employed to extract Eulaliopsis binata fibers in which NaOH as cooking agent and Na5P3O10 as auxiliary *** universal rotatable composite experiment design was used to get the highly precise regression equations,in which the NaOH concentration,the auxiliary agent Na5P3O10 concentration and the processing time were the main technological *** residual gum content,fiber fineness,fiber strength,and fiber length of Eulaliopsis binata were the evaluation *** on the relation among parameters of extracting process,degumming effect and quality indexs of Eulaliopsis binata fibers,the optimum parameters of extracting process on Eulaliopsis binata fibers can be *** fibers extracted from Eulaliopsis binata can be developed as one kind of natural cellulose fibers suitable for producing various textile products.

关键词： Eulaliopsis binata fibers extracting parameters optimization

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Studies on the pathogenic bacterium of ulcer disease in Epinephelus awoara

引用

Acta Oceanologica Sinica 2006年第1期25卷 154-159页

作者： QIN Yingxue WANG Jun SU Yongquan WANG Dexiang CHEN Xinzhong Department of Oceanography Institute of Subtropic Ocean Xiamen University Xiamen 361005 China Fisheries College Jimei University Xiamen 361021 China xiamen entry-exit inspection and quarantine bureau Xiamen 361012 China

Studies were conducted to determine the cause of the acute mortality of cage-cultured Epinephelus awoara in the Tong＇ an Bay of xiamen, China during the summer of 2002. Predominant bacteria strain TS-628 was isolated from the diseased grouper. The virulence test confirmed that TS-628 was the pathogenic bacterium. Biochemical characteristics of the isolates were determined using the automatic bacterial identification system and standard tube tests. To further confirm the identification, a 1 121 bp 16S rRNA gene sequence of the isolate was amplified by PCR, which had been deposited into Genbank （accession number： AY747308）. According to the biochemical characteristics and by comparing the 16S rRNA gene homology of the isolate, the pathogenic bacterium was identified as Vibrio harveyi, Drug sensitivity tests showed that this pathogenic bacterium was sensitive to 16 antibacterials, especially to chloramphenicol and actinospectacin, but completely resistant to antibacterials likes vancomycin, penicillin, lincomycin, and so on.

关键词： Vibrio harveyi Ep inephe lus awoara Ulcer disease

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：