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建立了饮用水源水中氯苯、二氯苯、三氯苯和四氯苯等共9种氯苯系化合物同时测定的吹扫捕集-气相色谱-质谱法(P&T-GC- MS).优化了吹扫捕集时间及解析时间,采用质谱的选择离子监测模式和内标定量法进行定量分析.在优化的吹扫捕集条件下,线性回归方程的相关系数均大于0.999 8;氯苯、二氯苯、三氯苯和四氯苯的方法检出限(... 相似文献
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基于多孔膜萃取水中挥发性有机物和微捕集技术,构建了一套水中挥发性有机物(Volatile OrganicCompounds,VOCs)样品前处理装置,可自动、在线、连续完成水中挥发性有机物萃取、富集、热解析,传输给气相色谱分离检测。实验分别对膜萃取材料、萃取温度、萃取时间、吹扫气流速等进行了系统优化,并用于氯仿、1,2-二氯甲烷、四氯化碳、三氯乙烯、甲苯、四氯乙烯、乙苯、氯苯、苯乙烯9种挥发性有机物的检测。研究结果表明,采用膜萃取/微捕集装置,与气相色谱联用,在萃取温度60℃,萃取时间30 min,吹扫气流速8 mL/min条件下,采用氢焰离子化检测器(Flame ionization detector,FID),对氯代烃的检出限达到0.003~0.041μg/L,精确度为2.7%~13.0%,线性相关系数均大于0.9936,适用于在线检测水中挥发性有机物。 相似文献
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目前卤乙腈作为我国非受监管的消毒副产物广泛存在于饮用出厂水中,可产生多种毒性,缺乏相关标准检测依据。研究建立了吹扫捕集-气相色谱-三重四极杆质谱同时测定饮用出厂水中氯乙腈、二氯乙腈、三氯乙腈、溴乙腈、溴氯乙腈、二溴乙腈的分析方法。吹扫捕集技术应用于卤乙腈的测定,实现了样品经采集后全程自动测定,有害试剂零消耗。同时吹扫捕集法相比固相微萃取法,样品制备的速度更快,成本更低。实验考察了样品6 h内目标组分的稳定性;比较了7#(2,6-二苯基对苯醚)、10#(2,6-二苯基对苯醚/硅胶/碳分子筛)、11#(疏水活性炭)、12#(疏水活性炭)捕集阱对目标组分响应的影响;考察了4种型号色谱柱(VF-5、Rxi-624、DB-VRX、HP-INNOWAX)对色谱峰形的影响。实验条件经优化,确定了吹扫捕集采用10#捕集阱,将25 mL水样于35 ℃吹扫11 min,于190 ℃解析1 min。气相色谱分流进样,分流比1∶10,使用Rxi-624Sil MS色谱柱(60 m×0.25 mm×1.40 μm)程序升温分离,线速度30 cm/s,在MRM模式下检测,外标法定量。结果表明,6种卤乙腈的基质效应为0.85~1.09,在各自范围内线性良好,r>0.9991,方法检出限为0.8~120.0 ng/L,定量限为1.5~300.0 ng/L, 3水平平均加标回收率为84.2%~106%,相对标准偏差(RSD)为1.81%~10.7%。对38份出厂水样品进行测定,卤乙腈总检出率为92.1%,含量为0.0101~1.28 μg/L。该方法高效、灵敏、环保,为针对卤乙腈类新兴消毒副产物开展监测及健康风险评估提供了优质的技术选择。 相似文献
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常温吹扫捕集-气相色谱法测定海水中氧化亚氮 总被引:4,自引:0,他引:4
建立了海水中氧化亚氮的常温吹扫捕集-气相色谱检测方法。对吹扫捕集系统的条件进行了考察,优化结果如下:捕集温度30℃,脱附温度250℃,吹扫时间10min,吹扫气流速20mL/min。等实验条件进行了优化。本方法操作简单、灵敏、重现;检出限达2.8×10-10mol/L,标准工作曲线的线性相关系数大于0.9995(n=5);曲线斜率的相对标准偏差为2.8%(n=5);回收率为93.93%±3.1%(n=5)。用此方法测定了厦门近海表层海水样品中氧化亚氮的浓度。 相似文献
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我国环境中有机污染物分析方法及痕量富集技术的进展 总被引:1,自引:0,他引:1
对有机污染物分析在近年进展作了评述。其主要内容涉及试样的预处理技术(如顶空法,吹扫-捕集法,固相萃取,半透膜等技术),各化合物的适用及有效的分析方法或仪器(如GC,HPLC及GC/MS等)以及各种技术及方法的联用技术等(引述文献37篇)。 相似文献
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赖永忠 《理化检验(化学分册)》2012,(8):941-942,945
苦味酸可与次氯酸钠反应生成的氯化苦(三氯硝基甲烷),用SPT37.50吹扫捕集仪吹扫、捕集及热解析后,经DB-624毛细管色谱柱分离,用电子轰击电离源及选择离子监测模式进行质谱分析。据此建立了吹扫捕集气相色谱质谱法间接测定饮用水源水中苦味酸含量的方法。苦味酸的质量浓度在25μg·L-1以内与其峰面积呈线性关系,方法检出限(3S/N)为0.9μg·L-1。样品加标回收率在86%~132%之间。 相似文献
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用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments. 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
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The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion. 相似文献
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The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula. 相似文献
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KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines. 相似文献
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
The review contains a concise historical account and information on the most significant researches undertaken by the staff
at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry
of Heterocyclic Compounds.
Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008. 相似文献
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N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%). 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献