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1.
采用吹扫捕集/气相色谱-质谱（GC-MS）法对水中13种挥发性卤代烃进行测定。通过调整吹扫温度和吹扫时间、解吸温度和解吸时间,分析吹扫捕集条件对吹扫捕集效率的影响,并确定最佳吹扫捕集条件。结果表明,在吹扫温度40 ℃、吹扫时间12 min、解吸温度240 ℃、解吸时间3 min的条件下,13种挥发性卤代烃的平均加标回收率为94.5％~106.7％,相对标准偏差为2.4％~5.5％,相关系数为0.999 1~0.999 9,最低检出限为0.03~0.28 μg/L。与国家标准方法相比,该方法操作简单、检出限 相似文献
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采用气相色谱(GC)法测定水产品中的甲基汞残留。样品前处理方法在HZ-HJ-SZ-0097(《环境甲基汞的测定气色谱法》)所规定的基础上,增加萃取溶剂体积;色谱条件优化如下院毛细管色谱柱Supelcowax-10(30m×0.53mm×0.5μm),柱温为210℃,进样口温度为210℃,ECD检测器温度为300℃,尾吹(N2)50mL/min,流速为7.0mL/min,不分流进样。测定结果表明,甲基汞的峰形尖锐,响应灵敏度高,标准的线性相关系数为0.9992,加标样品测定的相对标准偏差(RSD)为2.1%(n=6),最小检出限为0.1μg/kg,回收率均为85%～92%。测定结果显示,该方法具有快速、灵敏尧可靠尧简便尧重现性好等特点。 相似文献
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采用氢化物发生原子荧光法测定海南白沙绿茶和红茶中的硒含量，研究了仪器条件和还原剂等对硒原子荧光强度的影响。结果表明，最佳仪器条件为光电倍增管负高压300 V，灯电流80 mA；还原剂浓度为1.5%，载流盐酸浓度5%。该方法线性范围0～10 μg/L时，与荧光值线性关系好，回归方程为y＝75.949x－8.795 4，相关系数r＝0.999 8。方法检出限是0.024 μg/kg，测定标准物质中硒的回收率为97.7%～109.6%。以国家标准物质茶叶(GBW10016)为监控样品，标准物质茶叶测定值与标准值吻合。白沙绿茶和红茶硒元素含量分别是34.4和20.1 μg/kg。该方法线性范围宽、灵敏度高、检出限低，可用于茶叶等样品中硒元素含量的准确测定。 相似文献
4.
采用新型材料MonoTrap作为顶空固相萃取的吸附剂，捕集茉莉酸甲酯（MeJA）处理后的白木香愈伤组织挥发性成分，并应用GC-MS分析测定其化学成分及相对含量。结果表明，从MeJA不同处理下的白木香愈伤组织中共鉴定出56种挥发物成分，主要成分为脂肪烃类、芳香族类和倍半萜类等成分；通过正交实验法确定最佳捕集方法为：不破碎愈伤组织材料，于30 ℃条件下、采用MonoTrap捕集6 h。MonoTrap法结合气质联用具有高灵敏度、强针对性和可操作性强的优点，可以为白木香的开发利用提供理论依据。 相似文献
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橡胶小蠹虫为害重,防治困难。为了探索更加高效的田间防治方法,本研究通过将“牛皮纸+粘虫胶+诱集剂”组配,研究集成了一种橡胶小蠹虫粘捕装置,对其诱捕参数（粘捕装置材质、诱集剂药袋悬挂数量、药液暴露面积以及粘捕装置的间距、悬挂高度）进行了筛选,并与常规诱捕器在重量、成本和诱捕效果方面进行比较。结果表明,在月桂烯、2-甲基-3-丁烯-2-醇、S-(-)-柠檬烯、莰烯、顺式-马鞭草烯醇5种诱集剂的诱集下,自制粘捕带对橡胶小蠹虫的粘捕总数分别为：554、445、341、381、367头;普通粘虫带对橡胶小蠹虫的粘捕总数分别为：260、230、179、202、199头。其中月桂烯、2-甲基-3-丁烯-2-醇、S-(-)-柠檬烯,自制粘捕带的粘捕数量均显著高于普通粘虫带,表现出较好的粘捕效果。采用挂袋法的最佳药袋数为2袋,诱集剂的最佳药液暴露面积为6.6 mm2,粘捕装置的最佳相互间距为50 m,最佳悬挂高度建议在2.5 m。自制粘捕装置在重量、成本以及诱集数量上均优于常规诱捕器,对橡胶小蠹虫防控具有高效成本低、环保可降解、简单易操作等特点。 相似文献
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采用321型和717型阴离子混合交换树脂对海水中的重金属元素Cd、Cr、Pb、Cu、Ni和Zn进行分离预富集,以10%的硝酸溶液洗脱,ICP-AES法直接测定。结果表明,Cd、Cr、Pb、Cu、Ni和Zn能同时被阴离子交换树脂定量吸附。方法加标回收率在90.4%～105.8%,测定结果的相对标准偏差为0.96%～3.96%,方法的检出限为Cd 0.12、Cr 0.46、Pb 0.98、Cu 0.65、Ni 0.57和Zn 0.82 μg/L 。在优化的实验条件下,方法有较低的检出限,并且准确度和精密度令人满意。 相似文献
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研究利用于灰化法消解大豆色拉油，用氢化物发生-原子荧光法测定其中的痕量砷。对消化方法，样液介质及酸度，还原剂（KBH4）浓度，干扰离子，还原掩蔽剂等影响因素进行了探讨，得出试验的最佳条件。试验结果准确。灵敏度高，重现性好，方法简便，快速，适合于植物油中痕量砷的试验的最佳条件。试验结果准确，灵敏度高，重现性好，方法简便，快速，适合于植物油中痕量砷的测定。方法的回收率在86.9%-98.0%之间，线性范围为0-200ng/ml；检出限为0.19ng/ml。 相似文献
9.
目的研究氢化物发生一原子荧光光谱法的同时测定人参中砷和锑的含量。在仪器的最佳工作条件及氢化物发生条件下,还探讨了还原剂及其用量与还原掩蔽剂对测定的影响。方法采用氢化物一原子荧光光谱法进行测定。结果在测定条件下,砷的线性范围为0—10μg／L,r=0．9998,检出限为0．06μg/L,回收率102．3％,精密度（RSD）为3．45％;锑的线性范围为0-10μg／L,r=0．9999,检出限为0．027μg／L,回收率94．7％,精密度（RSD）为4．72％。用该法测定了标准物质茶叶中砷和锑的含量以进行比较,结果与推荐值相吻合。结论方法快速、准确,应用于人参中砷和锑的检测,获得较满意结果。 相似文献
10.
王草中水不溶性膳食纤维制备工艺研究 总被引：2，自引：0，他引：2
为提高王草综合利用水平,以王草为原料,采用化学水解法制备王草水不溶性膳食纤维,并探讨过氧化氢对其漂白效果的影响,测定其理化性质。结果表明,王草水不溶性膳食纤维最佳提取工艺条件为:提取温度55℃,NaOH质量浓度40g/L,提取时间120 min。该条件下提取率最高达到46.52%;最佳漂白工艺为过氧化氢浓度40 mL/L,时间2 h,温度50℃,pH值为9;王草水不溶性膳食纤维的膨胀力4.26 mL/g,持水力5.64 g/g。 相似文献
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Lakshman Lal 《Potato Research》1987,30(2):329-334
Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong
(1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage,
sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over
45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield
of a subsequent crop. 相似文献
13.
《Journal of Crop Improvement》2013,27(2):81-114
Summary The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices. 相似文献
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M. I. Siri P. Villanueva M. J. Pianzzola L. Franco Fraguas G. Galván M. Acosta F. Ferreira 《Potato Research》2004,47(3-4):127-138
Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results
for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin
presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear
relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins
and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds. 相似文献
16.
Novel food and non-food uses for sorghum and millets 总被引：4，自引：3，他引：4
Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity. 相似文献
17.
Alejandro Carlos Tozzini María Fernanda Ceriani María Verónica Saladrigas H. Esteban Hopp 《Potato Research》1991,34(3):317-324
Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets
that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and
slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging
toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta.
Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X1 (also called RXact). 相似文献
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Alejandro M. S. Mayer Abimael D. Rodríguez Orazio Taglialatela-Scafati Nobuhiro Fusetani 《Marine drugs》2013,11(7):2510-2573
The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories. 相似文献
19.
Chitosan is considered to be one of the most promising and applicable materials in adsorption applications. The existence of amino and hydroxyl groups in its molecules contributes to many possible adsorption interactions between chitosan and pollutants (dyes, metals, ions, phenols, pharmaceuticals/drugs, pesticides, herbicides, etc.). These functional groups can help in establishing positions for modification. Based on the learning from previously published works in literature, researchers have achieved a modification of chitosan with a number of different functional groups. This work summarizes the published works of the last three years (2012–2014) regarding the modification reactions of chitosans (grafting, cross-linking, etc.) and their application to adsorption of different environmental pollutants (in liquid-phase). 相似文献
20.
Alexander N. Shikov Elena V. Flisyuk Ekaterina D. Obluchinskaya Olga N. Pozharitskaya 《Marine drugs》2020,18(11)
Marine organisms represent an excellent source of innovative compounds that have the potential for the development of new drugs. The pharmacokinetics of marine drugs has attracted increasing interest in recent decades due to its effective and potential contribution to the selection of rational dosage recommendations and the optimal use of the therapeutic arsenal. In general, pharmacokinetics studies how drugs change after administration via the processes of absorption, distribution, metabolism, and excretion (ADME). This review provides a summary of the pharmacokinetics studies of marine-derived active compounds, with a particular focus on their ADME. The pharmacokinetics of compounds derived from algae, crustaceans, sea cucumber, fungus, sea urchins, sponges, mollusks, tunicate, and bryozoan is discussed, and the pharmacokinetics data in human experiments are analyzed. In-depth characterization using pharmacokinetics is useful for obtaining information for understanding the molecular basis of pharmacological activity, for correct doses and treatment schemes selection, and for more effective drug application. Thus, an increase in pharmacokinetic research on marine-derived compounds is expected in the near future. 相似文献