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1.
Temperature-programmed retention indices for eleven cyclic organic peroxides were determined by gas chromatography on slightly
polar 5% biphenyl 95% dimethylpolysiloxane columns (DB-5 and Rtx-5MS) at three heating rates (5, 10, and 20° min−1) from 60 to 300°C, using different chromatographs. Cyclic organic diperoxides and triperoxides had nearly constant retention
indices when different heating rates and a short isothermal hold time (5 min) before the programmed increase in temperature
were used. The usefulness of temperature-programmed retention indices was shown by using the data to predict the retention
times and structures of unknown diperoxides or triperoxides derived from ketones. This is the first step in the identification
of unknown cyclic organic peroxides, a process would otherwise require the availability of reference compounds.
Revised: 7 and 17 November 2005 相似文献
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A method was proposed for calculating the thermodynamic properties, freezing point depression, boiling point elevation, vapor
pressure and enthalpy of vaporization for single solute electrolyte solutions, including aqueous and nonaqueous solutions,
based on a modified three-characteristic-parameter correlation model. When compared with the corresponding literature values,
the calculated results show that this method gives a very good approximation, especially for 1-1 electrolytes. Although the
method is not very suitable for some solutions with very high ionic strength, it is still a very useful technique when experimental
data is scarce. 相似文献
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反相薄层色谱法分析有机过氧化物的研究 总被引:2,自引:0,他引:2
本文研究了利用C_(18)。反相薄层板,以乙腈水溶液为展开剂,硖化钾为显色剂分析某些有机过氧化物如过氧化羟基异丙苯、过氧化环己酮和过氧化苯甲酰以及过氧化氧,得到较好的分离效果。同时,利用薄层扫描仪对过氧化苯甲酰进行定量分析研究,工作曲线线性范围为0.14~7.0μg/2μl,检出限为40ng。将该方法应用于测定面粉和化妆品中过氧化苯甲酰的含量,回收率试验均取得满意的结果。薄层板经甲醇适当处理后可反复多次使用。 相似文献
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以甲醇或甲醇与水作流动相,ODS为固定相,测定环己酮的多种过氧化物。平均回收率100.2%~101.6%,测定的相对标准偏差为1.02%~2.51%。 相似文献
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在非质子极性溶剂-二甲基乙酰胺中,室温下用碘乙烷与C_1—C_6脂肪酸及乳酸的四甲基铵盐反应制备各酸相应的乙酯。乙酯在15%的邻苯二甲酸二壬酯与6%的土温-80混合固定液填充柱上获得满意分离。用本法测定饮料酒中的低沸点有机酸含量,简便、快速、准确。 相似文献
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气相色谱法分离测定空气中的有机胺类物质 总被引:3,自引:0,他引:3
本文对空气中有机胺类物质的气相色谱分离和定量测定进行了系统研究。样品经富集,分离浓缩后,可以实现对三甲胺,甲胺,乙胺的色谱分离。对排出量大、嗅觉阈值低的三甲胺(0.00021μg/ml)进行了GC定量研究,其最小检出量为0.1μg/ml,回收率达96~100%。本方法简便、快速、灵敏、准确。可用于现场样品测定。 相似文献
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We calculate the heats of vaporisation for imidazolium‐based ionic liquids [Cnmim][NTf2] with n=1, 2, 4, 6, 8 by means of molecular dynamics (MD) simulations and discuss their behavior with respect to temperature and the alkyl chain length. We use a force field developed recently. The different cohesive energies contributing to the overall heats of vaporisations are discussed in detail. With increasing alkyl chain length, the Coulomb contribution to the heat of vaporisation remains constant at around 80 kJ mol?1, whereas the van der Waals interaction increases continuously. The calculated increase of about 4.7 kJ mol?1 per CH2‐group of the van der Waals contribution in the ionic liquid exactly coincides with the increase in the heats of vaporisation for n‐alcohols and n‐alkanes, respectively. The results support the importance of van der Waals interactions even in systems completely composed of ions. 相似文献
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Small organic acids have shown significant retention on various stationary phases, such as amide, amino, aspartamide, silica
and sulfobetaine phase commonly used in hydrophilic interaction chromatography (HILIC). This study investigated the effect
of chromatographic conditions on the retention behavior of organic acids in HILIC using the tool of design of experiment (DOE).
The results of the DOE study indicated that both the content of organic solvent (i.e., acetonitrile) and salt concentration
in the mobile phase had significant effects on the retention of organic acids. Higher content of organic solvent in the mobile
phase led to a significant increase in retention on all types of stationary phases. Increasing salt concentration also resulted
in a moderate increase in retention; however, the effect of salt concentration varied with the type of stationary phase. The
study also revealed that column temperature had less impact on retention than organic solvent content and salt concentration
in HILIC. 相似文献
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土壤中绿黄隆残留量分析方法的研究 总被引:2,自引:0,他引:2
本文确立了土壤中绿黄隆残留量的间接气相色谱分析方法,用0.15mol/L NaHCO3提取土样,二氯甲烷洗涤初步纯化后,在水浴上加热水解,再用二氯甲烷萃取,弗罗里硅土柱净化,最后用气相色谱-电子捕获检测器检测水解产物邻氯苯磺酰胺。土壤中添加回收率78.5%-90.8%,检测极限0.3ng/g。 相似文献
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芦笋根中菝葜皂甙元的气相色谱测定 总被引:6,自引:0,他引:6
芦笋根粉末经提取,分离得到菝葜皂甙元。利用GC-MS,IR,并与气相色谱保留值比较进行定性分析,气相色谱外标法定量测定,同时考察了气相色谱定量测定的回收率和水解时间对测定值的问题,实验结果表明,风干芦笋根中菝葜皂甙元的含量在1%以上。 相似文献
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以离子交换法对尿样中的多胺进行预分离富集,确定了最佳的离子交换条件,同时比较了三种不同酰化剂的酰化效果,确定了最佳酰化条件,并用毛细管气相色谱法测定了尿中腐胺,尸胺,精脒,精胺的含量,结果表明癌症病人尿中多胺含量高于正常人。 相似文献
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应用毛细管气相色谱-质谱轮廓分析方法,测定了33例2.5~4.5岁健康儿童尿中有机酸种类及含量和8例拟诊为苯丙酮尿症儿童尿中的有机酸,结果表明患儿尿样中苯丙酮酸、苯乙酸、邻羟基苯乙酸、对羟基苯乙酸高于正常值10~470倍。为苯丙酮尿症的确诊提供了可靠方法。 相似文献
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快速气相色谱法测定蔬菜中菊酯类农药残留量 总被引:19,自引:0,他引:19
采用一种较快速,简单的方法测定蔬菜中菊酯类农药残留物。样本中农残经乙酸酯萃取,凝胶渗透色谱及固相提取净化后,用气相色谱-电子捕获检测器测定,色谱柱为HP-5小口长石英毛细管柱。本法对6种常用菊酯类农药的回收率范围为89.6%-99.7%,检测限为0.04mg/kg。对同一批普施用菊酯类农药的白菜样本进行化验,本法跟美国食物及药品管理局农药残留标准测定方法所得结果非常吻合。 相似文献