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表面解吸常压化学电离质谱直接测定香辛蔬菜化学指纹 总被引:1,自引:1,他引:0
采用表面解吸常压化学电离质谱技术在无需样品预处理的前提下,对香辛蔬菜如韭菜、洋葱和大蒜的挥发性成分进行了快速检测,并对部分成分进行了二级串联质谱分析。 结果表明,韭菜叶片挥发性主要成分为2-甲基-2-戊烯、二甲基硫代亚磺酸酯、甲基烯丙基硫代亚磺酸酯等,其中二甲基硫代亚磺酸酯和甲基烯丙基硫代亚磺酸酯产生较强的M+H2O·+信号。 未切开的洋葱鳞茎挥发性成分质谱信号较弱,质谱图中主要是一些电晕放电产生的初始离子信号。 切开后的洋葱鳞茎挥发性成分质谱信号明显增强,主要是丙烯基次磺酸、丙基烯丙基硫代亚磺酸酯和二丙基硫代亚磺酸酯。 大蒜鳞茎挥发性成分主要是二烯丙基硫代亚磺酸酯。 切开后的大蒜鳞茎挥发性成分主要是丙烯基次磺酸。 实验对韭菜的二甲基硫代亚磺酸酯和甲基烯丙基硫代亚磺酸酯、洋葱的丙烯基次磺酸、大蒜的二烯丙基硫代亚磺酸酯进行了二级串联质谱分析。 表面解吸常压化学电离质谱技术无需样品预处理,分析速度快且对样品不造成破坏。 相似文献
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《应用化学》2010,(5)
采用表面解吸常压化学电离质谱技术在无需样品预处理的前提下,对香辛蔬菜如韭菜、洋葱和大蒜的挥发性成分进行了快速检测,并对部分成分进行了二级串联质谱分析。结果表明,韭菜叶片挥发性主要成分为2-甲基-2-戊烯、二甲基硫代亚磺酸酯、甲基烯丙基硫代亚磺酸酯等,其中二甲基硫代亚磺酸酯和甲基烯丙基硫代亚磺酸酯产生较强的M+H2O.+信号。未切开的洋葱鳞茎挥发性成分质谱信号较弱,质谱图中主要是一些电晕放电产生的初始离子信号。切开后的洋葱鳞茎挥发性成分质谱信号明显增强,主要是丙烯基次磺酸、丙基烯丙基硫代亚磺酸酯和二丙基硫代亚磺酸酯。大蒜鳞茎挥发性成分主要是二烯丙基硫代亚磺酸酯。切开后的大蒜鳞茎挥发性成分主要是丙烯基次磺酸。实验对韭菜的二甲基硫代亚磺酸酯和甲基烯丙基硫代亚磺酸酯、洋葱的丙烯基次磺酸、大蒜的二烯丙基硫代亚磺酸酯进行了二级串联质谱分析。表面解吸常压化学电离质谱技术无需样品预处理,分析速度快且对样品不造成破坏。 相似文献
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以4,5-二(2'-氰乙基硫基)-1,3-二硫杂环戊烯-2-硫酮为原料经甲醇钠消除一个氰乙基生成4-(2'-氰乙基硫基)-1,3-二硫杂环戊烯-2-硫酮的单钠盐, 生成的单钠盐再与1,4-二(氯甲基)苯反应生成4,4'-二(2-氰乙基硫基)-5,5'-(1,4-二亚甲基苯)-二(1,3-二硫杂环戊烯-2-硫酮). 接着在乙酸汞的作用下生成4,4'-二(2-氰乙基硫基)-5,5'-(1,4-二亚甲基苯)-二(1,3-二硫杂环戊烯-2-酮), 此化合物在亚磷酸三乙酯的作用下发生偶联反应, 生成由TTF单元和苯单元构建的新型四硫富瓦烯环蕃和另一种四硫富瓦烯衍生物. 并分别通过循环伏安法和化学氧化法对它们及其导电复合物的电化学性质和紫外光谱进行了研究. 还研究了这种新型四硫富瓦烯环蕃在金纳米颗粒表面自组装行为. 相似文献
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本文研究了苯基硫脲、苯基二氯化膦与脂肪醛(酮)在无水苯中进行的类Mannich反应,在分离产物时发现,除了生成3,4-二苯基-4-氧代-1,3,4-二氮磷杂环戊-2-硫酮(Ⅰ)外,还得到了少量3,4-二苯基-4硫代-1,3,4-二氮磷杂环戊-2-硫酮(Ⅱ).根据化合物Ⅱ的生成及31PNMR跟踪反应的结果,得出反应机理为P-H键对亚胺衍生物的加成.通过X射线衍射分析发现,化合物Ⅰ和Ⅱ的五元杂环均为平面结构,其平面性受4位氧代或硫代的影响较大. 相似文献
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冷柱头程序升温进样-气相色谱/质谱法研究新鲜大蒜中的有机硫化合物 总被引:4,自引:0,他引:4
采用冷溶剂提取新鲜大蒜中的有机硫化合物,结合冷柱头程序升温进样,对大蒜原始组分进行了气相色谱/质谱分析 。该法实现了从提取到色谱分离的“冷过程”,因而可以准确地鉴定大蒜提取液在热分解前的原始组分。分析结果表明, 在大蒜提取液中含有3-乙烯基-1,2-二硫杂-5-环己烯及其异构体2-乙烯基-1,3-二硫杂-4-环己烯两种主要组分以及少量 的S-甲基甲烷硫代亚磺酸酯、二烯丙基二硫醚、二烯丙基三硫醚。对大蒜的冷溶剂提取液和水蒸气蒸馏提取的大蒜油中 的有机硫化合物进行了比较,对一些主要有机硫化合物的形成进行了初步探讨。 相似文献
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3-苯基-4-氯-1,3,4-二氮磷杂环戊-2-硫酮的合成及其除草活性研究 总被引:1,自引:0,他引:1
报道了苯基硫脲与脂肪醛(酮)及三氯化磷进行的类Mannich反应,除生成预期产物3-苯基-4-氯-4-氧代-1,3,4-二氮磷杂环戊-2-硫酮(Ⅰ)外,还生成了少量3-苯基-4-氯-4-硫代-1,3,4-二氮磷杂环戊-2-硫酮(Ⅱ).当Ⅰ与Lawesson试剂在甲苯中反应时,可顺利地转化为Ⅱ.生物测定结果表明,Ⅱ具有较好的选择性除草活性.晶体结构测定表明,Ⅱ的五元磷杂环为平面结构. 相似文献
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Livia Maria Zambrozi Garcia Passari Ieda Spacino Scarminio Roy Edward Bruns 《Analytica chimica acta》2014
Statistical design mixtures of acetone, chloroform, dichloromethane and ethanol were used to study the effects of different solvents and their mixtures on the quantities of coumarin and related metabolites extracted from Mikania laevigata samples harvested in each of the four seasons. RP-HPLC-DAD and both positive and negative modes of UPLC-MS analyses were used to determine relative quantities of coumarin, o-coumaric acid and melilotic acids in each season for all the mixture design extracts. The existence and measurement of the relative abundances of melilotic acid in Mikania laevigata have not been reported previously. Highest coumarin concentrations were encountered in the summer whereas its o-coumaric acid precursor and melilotic acid were most abundant in the spring. O-coumaric and melilotic acids concentrations were strongly correlated during the year. Also solvent effects were seen to be significant. Ethanol and 1:1 binary mixtures of ethanol and acetone extracted the largest quantities of coumarin whereas ethanolic binary and ternary mixtures with chloroform and dichloromethane provided the best yields of o-coumaric and melilotic acids. Statistical mixture models indicated that synergic binary interactions, especially those involving ethanol with acetone or chloroform, are important in the Mikania extraction process. 相似文献
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Sequential ultrasonic extraction of a Chinese coal and characterization of nitrogen‐containing compounds in the extracts using high‐performance liquid chromatography with mass spectrometry 下载免费PDF全文
Jun‐Liu Xia Xing Fan Chun‐Yan You Xian‐Yong Wei Yun‐Peng Zhao Jing‐Pei Cao 《Journal of separation science》2016,39(13):2491-2498
Dongming lignite was sequentially extracted with petroleum ether, carbon disulfide, methanol, acetone, and isometric carbon disulfide/acetone mixed solvent at room temperature to afford extracts 1–5, respectively. High‐performance liquid chromatography coupled with electrospray ionization time‐of‐flight mass spectrometry was used to separate and characterize heteroatomic species in the extracts at molecular level. Molecular mass of compounds in the extracts is mainly distributed from 300 to 800 u, and the relative abundance of compounds with molecular mass over 800 u in the carbon disulfide extract is 135 times of that in the petroleum ether extract. The acetone extract has the highest relative abundance for organonitrogen compounds. Double bond equivalence numbers of detected species indicate that most of the organonitrogen compounds contain N‐heterocyclic aromatic rings, including pyridine, quinoline and pyrrole. Some organonitrogen isomers in Dongming lignite were separated and identified by high‐performance liquid chromatography coupled with electrospray ionization time‐of‐flight mass spectrometry, and the corresponding structural information was proposed. 相似文献
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The performance of ultrasonic and Soxhlet extraction using hexane, dichloromethane, ethylacetate/methyl-tert-butylether (1/3, v/v) and hexane/acetone (1/1, v/v) for the analysis of seventeen insecticides in sediments was evaluated. The contents of the extracts differed severely. The extracts obtained with ethylacetate/methyl-tert-butylether (1/3, v/v) and hexane/acetone (1/1, v/v) were dark yellow to green, whereas the extracts obtained with dichloromethane and hexane were light yellow and clear respectively. This is due to higher solubility of matrix compounds in ethylacetate/methyl-tert-butylether (1/3, v/v) and hexane/acetone (1/1, v/v). High loads of coextracted matrix compounds lead to matrix effects in the evaporation step of GC–MS measurements. This is known as matrix induced response enhancement effect. Matrix effects and recoveries were checked by analysis of spiked sediments. The suitable choice of extraction method in connection with an appropriate solvent separates the analytes from matrix compounds. Matrix effects are reduced and recoveries of spiked samples are improved.Revised: 6 January and 2 May 2005 相似文献
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Paola Bocchini Danilo Dello Monaco Romina Pozzi Francesca Pinelli Guido C. Galletti 《Mikrochimica acta》2009,165(3-4):271-278
A solid-phase microextraction (SPME) method was developed for air monitoring of organic solvents frequently used in chemical laboratories (namely pentane, dimethyl ether, acetone, acetonitrile, dichloromethane, hexane, ethylacetate, tetrahydrofurane, cyclohexane, benzene, and toluene). SPME sampling conditions and chromatographic separation were optimised. Linearity of response for each component of the mixture was tested. Standard solutions containing all the compounds, at three different concentrations, were analysed in triplicate and the relative standard deviations (RSDs) were calculated. The method was applied to the monitoring of indoor air in a research chemical laboratory. An SPME fibre was used as a sampling device inside the laboratory. Moreover an SPME fibre was used as a portable sampling device in order to determine the effective human exposure. Comparison of the portable and fixed sampling device showed differences in the amount of solvents associated with activities performed nearby. 相似文献
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Yields of extracted substances, as well as total phenol and flavonoid compounds obtained by classical and ultrasonic extractions from dry leaves of two tobacco types (oriental and Virginia) by two different solvents (acetone and methanol) at two operating temperatures (25 and 40 degrees C) were compared. The yield of extractive, as well as total phenol and flavonoid compounds depended on the type of solvent, operational temperature and the tobacco type. The importance of these factors was assessed using 2(4) full factorial experiments without replication. 相似文献
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J Mes D Davies F Bryce 《International journal of environmental analytical chemistry》1983,15(1):25-37
The extraction efficiency of benzene, toluene, dichloromethane, acetone:hexane and chloroform:methanol with respect to lipids and polychlorinated biphenyls was investigated using small samples of monkey adipose tissue, liver, kidney, brain, skin, feces and milk. The most efficient solvents were: acetone:hexane and chloroform:methanol for brain, feces, kidney, liver and milk; acetone:hexane and dichloromethane for adipose tissue; acetone:hexane and toluene for blood and dichloromethane for skin tissue. Within these solvent pairs acetone:hexane was the most outstanding with respect to an average of 90% PCB recoveries from fortified samples in the range of 0.02-2 ppm. In addition, a comparison was made between the lipid determination before and after Florisil column chromatography. Only adipose and blood lipids were sufficiently recovered from Florisil to make a lipid determination after chromatography feasible. 相似文献
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便携式气相色谱-质谱联用仪现场测定畜禽粪便堆肥中挥发性有机物 总被引:8,自引:0,他引:8
采用便携式气相色谱-质谱联用仪进行了畜禽粪便堆肥排放气体中挥发性有机物质的现场分析.结果表明,在堆肥排放气体中可检测到含硫物质、脂肪烃、芳香烃及含氯有机物共20种物质.在已定量的8种物质中,CS2浓度最高,达到204 mg/m3;CS2和二甲二硫超过《恶臭污染物排放标准》(GB1455-93)的限值;SO2和苯超过《室内空气质量标准》(GB/T 18883-2002)的限值.本方法避免了常规检测中易出现的组分分解等问题,SO2测定值较常规方法提高59.3%.本方法操作方便,结果准确,适于对挥发性有机化合物的在线监测. 相似文献
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M. A. Proskurnin S. N. Bendrysheva V. V. Kuznetsova A. A. Zhirkov B. K. Zuev 《Journal of Analytical Chemistry》2008,63(8):741-750
The effect of the main parameters of the solvents (water, acetone, methanol, ethanol, acetonitrile, dimethyl sulfoxide, dichloromethane, toluene, and chloroform) that are most frequently used in the analytical practice on the characteristics of the thermal lens effect (increase in temperature because of optical heating and in the size of the region involved in heating) and on the detection limit and the lower determination limit of the thermal lens determination was considered, and the criteria of the selection of the medium for thermal lens experiments were discussed. It was demonstrated that the gain in these characteristics of the thermal lens determination in the given medium in comparison with the aqueous medium does not necessarily coincide with the strength of the thermooptical effect in this medium. It was demonstrated that the optimum conditions of measurements in the thermal lens detection are controlled not only by the absorption of the analyte and the reagents, but also by the intrinsic absorption of the solvent. Recommendations were given on the selection of the solvent for analytical thermal lens spectrometry. 相似文献