气相色谱-质谱法分析茶叶中常见的15种农药残留

目的：利用气相色谱-质谱法同时检测茶叶中有机氯,拟除虫菊酯,有机磷多种农药残留。方法：茶叶试样用二氯甲烷提取后经无水硫酸钠脱水,活性炭脱色,再用凝胶色谱柱净化,净化液浓缩并定容后,供色相色谱-质谱（GC-MS）测定和确证,外标法定量。结论：气相色谱-质谱法分析茶叶中农药残留量快速、高效,重现性、回收率较好,符合实际检验要求。     

气相色谱法测定茶叶中菊酯类农药残留

近年来,茶叶的安全卫生已经在国际贸易中成为一种技术壁垒.如何用科学的方法,快速、准确地检测出茶叶中农药的残留量,对正确使用农药,提高茶叶质量,扩大出口起着重要作用.菊酯类农药是一类广谱性杀虫剂,具有高效、低毒、低残留等优点,近年来广泛用于茶园虫害的防治.本文介绍一种用气相色谱法测量茶叶中氯氰菊酯、氰戊菊酯、溴氰菊酯残留的方法.该方法采用微量化学法和固相萃取技术对样品进行提取及净化处理,在实际应用中效果较为理想.     

气相色谱-质谱法测定茶叶中42种残留农药

粉碎后的茶叶使用乙腈超声提取,再经石墨化碳固相萃取柱净化,采用气相色谱-质谱法(GC-MS)的选择离子监测（SIM）方式和外标法定量方法,同时分析测定了茶叶中的42种农药(12种有机氯、9种拟除虫菊酯、20种有机磷和戊唑醇)残留量。该方法回收率在62.5%～120.1%之间,相对标准偏差小于15.1%,42种农药的检出限最低为0.3μg/kg,最高为9.2μg/kg。该方法快速、灵敏、准确,各项技术指标满足国内外农药残留检测的要求,能够应用于茶叶试样中痕量农药残留的分析。     

基质固相分散萃取测定茶叶中农药多残留初探

文章建立了一个简单快速、能同时分析茶叶中多种农药残留的新方法。采用一种新的样品前处理方法——基质固相分散(Matrix Solid-Phase Dispersion,MSPD)萃取替代传统的液-液萃取、固相萃取,从茶叶中提取、净化14种常用农药残留,采用GC-FPD分析检测;14种农药的回收率在65.4%~110.6%之间,相对标准偏差小于19.3%,LOD为5.0~30.0μg/L,LOQ为25.0~100.0μg/L。     

茶叶中农药残留分析技术研究进展

查阅近些年国内外公开发表的文献,简述了我国茶叶生产上常用农药情况,比较了国内外茶叶农药残留最大限量标准,综述了茶叶中农药残留的主要检测技术,重点对固相微萃取法、液相微萃取法、分散固相萃取法等样品前处理技术,以及气相色谱法、液相色谱法、质谱法、免疫分析法等检测技术在茶叶农药残留分析中的应用及特点进行了总结,并对其发展方向进行了展望,以期为今后开展茶叶中农药残留的分析研究提供参考。     

国内外茶叶农药最大残留限量标准比较分析

我国出口茶叶中经常检出农药超标,严重影响其国际竞争力。通过对我国茶叶农药最大残留限量(MRLs)标准与国际食品法典委员会(CAC)以及欧盟、日本、澳大利亚等发达国家茶叶农药最大残留限量标准的比较分析,找出我国与国外茶叶农药最大残留限量标准的差距,了解各国茶叶农药最大残留限量标准的最新动态,并对差异进行了分析研究,为完善我国茶叶农药最大残留限量标准提出参考建议,对提升我国茶叶出口竞争具有重要意义。     

超声提取-分散固相萃取-气相色谱法测定绿茶中有机磷类农药残留

应用超声辅助提取和分散固相萃取前处理方法结合气相色谱（配火焰光度检测器）建立了绿茶中13种有机磷类农药残留的快速分析方法.5 g茶叶样品用20 m L乙腈（含1%乙酸）超声辅助提取后,以石墨化炭黑与伯仲胺混合型固相分散净化,高速离心后氮吹浓缩复溶,过滤膜,用气相色谱-火焰光度检测器进行检测.在0.02-0.10 mg/kg的添加水平,13种有机磷农药的平均回收率是84.78%-116.72%,相对标准偏差是0.12%-9.32%,检出限是0.000 8-0.01 mg/kg.本方法简便快速,准确性好,成本低,该方法已用于市面上销售的绿茶产品中有机磷类农药残留测定,结果均低于国家标准GB 2763—2012的最大残留量要求.     

气相色谱-质谱法测定苹果中多种农药残留

通过对苹果中多种农药残留进行定性定量分析,考察方法的可行性与可靠性.用丙酮-己烷混合液(V丙酮∶V己烷=20∶80)溶液对苹果匀浆液进行提取,通过Florisil固相萃取柱净化苹果提取液,采用气相色谱-质谱对苹果中多种残留农药进行测定,以保留时间和特征离子定性定量;本方法测定了苹果中包括有机磷、有机氯、氨基甲酸酯类在内的50种农药,通过色谱和质谱对每一农药都进行了定性分析,86%农药的添加回收率都在70%～103%之间,相对标准偏差在0 2%～6 0%之间;证明了采用丙酮-己烷混合液(V丙酮∶V己烷=20∶80)溶液、Florisil固相萃取柱对苹果进行提取、净化,再用气相色谱-质谱分析多种农药残留的方法是可行的,可以作为针对多农药残留的分析方法.     

毛细管气相色谱法同时测定蔬菜中9种菊酯类农药残留量

对3种不同种类蔬菜中残留的9种菊酯类农药的提取、净化及气相色谱测定方法进行了研究．样品采用乙腈提取,固相萃取柱[SFC Florisil-（1g）]净化,并采用GC-ECD法同时测定样品中9种菊酯类农药的残留量．方法检出限为0．0004～0．0040mg·kg^-1,平均回收率为84．3％～101.1％,相对标准偏差为1．5％～2．7％．该方法的样品预处理简单,分析速度快,结果准确可靠,能满足实际样品分析．     

GC-NCI-MS分析粮谷中多类农药残留

 建立了粮谷中14种农药残留（9种有机氯、3种拟除虫菊酯和2种含氯有机氮）气相色谱-负化学源-质谱（GC-NCI-MS）的分析方法,试样样品用V(正己烷)∶V(丙酮)=1∶1超声波提取,硅镁吸附剂净化,采用GC-NCI-MS选择离子扫描方式检测.结果表明,该方法准确、快速、选择性好、抗干扰能力强,14种农药的方法最低检出限：0.01～0.18?μg/kg,平均添加回收率在75.2%～109.7%之间,变异系数都小于10%,并成功应用于大米、面粉试样中痕量农药残留分析.     

Markedness and its Interpretation in Language Use

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

The Analects and the Moment in Peking——The influence of a Confucian education system on the personality formation,the way of thinking and the fate of the main characters

0.Preface China has long been boasting of its colorful and immense culture which comprises of Taoism,Confucianism and Buddhism.The interwoven influence among the religions on Chinese way of thinking,on the nation＇s behavior in their social life throughout the long history is beyond list.