共查询到19条相似文献,搜索用时 892 毫秒
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本文通过离子色谱的保留值方程研究了离子的特征参量与其色谱保留之间的定量关系,其结果表明,色谱条件一定时,通过离子的特征参量,可以对保留值加以预测。 相似文献
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对月桂酸、豆蔻酸、棕榈酸、油酸、亚油酸、亚麻酸、花生酸、花生烯酸、山嵛酸、芥酸、α-桐酸、蓖麻油酸等12种脂肪酸的气相色谱保留值与其化学结构的关系进行了探讨。计算了这些脂肪酸的部分分子连接性指数。采用多元线性拟合法,求出了各脂肪酸分子中各种碳原子的个数及分子连接性指数与其气相色谱保留关系的回归方程,得到了复相关系数≥0.99,F检验值远高于临界值的回归方程,方程预测的色谱保留值与文献值一致。 相似文献
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通过对硫醚类化合物在不同固定相不同柱温下的366个样本的气相色谱保留指数值(RI)与其部分参数:拓扑指数(mQ)、固定液极性值(CP)及柱温(T)建立定量-色谱保留相关(QSRR)模型.分别利用多元线性回归(MLR)、偏最小二乘回归(PLSR)、人工神经网络(ANN)建模,同时采用内部及外部双重验证的办法对所得模型稳定性能进行深入分析和检验,建模计算值、留一法(LOO)交互检验(CV)预测值和外部样本的复相关系数Rcum、QLOO和Rext分别为0.9812,0.9804和0.9818(MLR);0.9812、0.9807和0.9818(PLSR);0.9869、0.9867和0.9827(ANN).结果表明:所建定量结构保留关系(QSRR)模型具有良好的稳定性和预测能力,较好地揭示了硫醚化合物在不同固定相不同柱温上气相色谱保留指数的变化规律. 相似文献
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对 8种氨基甲酸酯类农药和 8种酰胺类农药的高效液相色谱分析法进行了探讨。使用 ODS- C1 8(5μm)为固定相的 15 0 m m× 4.6 mm(i.d.)的不锈钢柱及甲醇 -水流动相 ,进行了这 16种农药的高效液相色谱测定。同时应用化学计量学的原理 ,对这些农药的定量结构与其色谱保留值的关系进行了研究。采用多元线性回归法 ,建立了试验农药的分子连接性指数以及理化参数与其色谱保留值关系的回归方程 ,能得到用这些方程的计算值与实验测定的保留值一致的结果 相似文献
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用分子形状指数估算氯代羟基苯甲醛的气相色谱保留指数 总被引:2,自引:0,他引:2
基于化学拓扑理论,计算了25种氯代羟基苯甲醛衍生物的分子形状指数(mK)。用多元回归方法研究了这些化合物的气相色谱保留指数(RI)与mK及取代基距离参数(L)的定量关系。经逐步回归分析,建立了最佳的定量结构-色谱保留指数的二元相关(QSRR)模型,其相关系数(R)为0.991。用Jackknife法检验该模型具有良好的稳健性与预测能力,其计算值与实验值基本吻合。 相似文献
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用相关指数估算氯代羟基苯甲醛的色谱保留指数 总被引:1,自引:0,他引:1
基于化学拓扑理论,计算了25种氯代羟基苯甲醛衍生物的电拓扑状态指数(En)、连接性指数(mXpv)。用多元回归研究了这些化合物的色谱保留指数(R.I.)与En、mXpv的定量关系。经逐步回归分析,建立了最佳的定量结构—色谱保留指数相关(QSRR)模型:R.I.值=-649.379+824.837E6+461.0301Xvp,n′=22,R=0.988,F=398.22,S=28.78。用Jackknife法检验具有良好的稳健性与预测能力,其计算值与试验值基本吻合,优于文献结果。 相似文献
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文章选用硫醚类化合物作为研究对象,研究了化合物结构与气相色谱保留指数的相关关系。用多元线性回归法构建了30个硫醚类化合物的QSRR模型,研究了此类化合物在四种不同极性固定相上的保留行为,得到的QSRR方程均具有高度的相关性,且经验证方程的稳定性和可靠性良好。 相似文献
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The separation of ethylene-propylene-diene terpolymers (EPDM) according to the three monomer units is an important task to understand the macroscopic properties of these technically important elastomers. In particular a separation with regard to the content of diene is of extreme value because the distribution of the latter along and across the molar mass axis determines the cross-linking behavior. In this study we show that high-temperature liquid chromatography (HT-HPLC) can be used for this purpose: the chromatographic retention of EPDM on porous graphite using a gradient of 1-decanol→trichlorobenzene is a function of both the content of ethylene and diene. The contribution of the diene alone to the chromatographic retention can be quantified by calculating the difference in elution volume between the EPDM and an EP copolymer having an equivalent content of ethylene. The chromatographic separation of fully hydrogenated EPDM indicates that the additional retention due to diene is the result of its geometrical nature. Coupling the HPLC separation according to the chemical composition with size exclusion chromatography (SEC) enables to reveal for the first time the complete molecular heterogeneity, i.e. the relationship between the chemical composition distribution and the molar mass distribution of EPDM. 相似文献
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根据保留指数随温度变化的关系式得出保留指数随温度变化的三种规律,运用气相色谱实验获得了较好的验证;并从色谱热力学函数分析了保留指数随温度变化规律的主要原因是由于在色谱分离过程中不同的熵变和焓变所造成的。 相似文献
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Natural Waxes XVI: Gas Chromatography of Wax Esters The authors have applied the method of high temperature gas chromatography of wax esters in the study on relationship between position of ester group in the carbon chain on the retention volumes of isomeric esters. In esters containing one double bond variations in retention data were observed. Gas chromatography and mass spectroscopy revealed that inspite of its apparent simplicity, spermaceti-ester is actually a complex mixture of esters, since each gas chromatographic peak, corresponding to a definite carbon number, contains a mixture of isomeric esters. These esters differ from each other only with respect to position of their ester group. 相似文献
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《分离科学与技术》2012,47(2):236-243
In this work, the principles of multi-criteria decision-making were used to develop an efficient optimization strategy in gradient elution ion chromatographic analysis. Two different artificial neural network retention models (multi-layer perceptron and radial basis function), three different separation criterion functions (chromatography response function, separation factor product and normalized retention difference product), and four different robustness criterion functions (CR1-CR4) were examined. The shape of the calculated separation vs the robustness response surface was used as principal criterion. Analysis time and minimum separation of adjacent peaks were additional criteria. The results showed that the radial basis artificial neural network retention model in combination with normalized retention difference product separation criterion function and CR3 robustness criterion function provided the optimal gradient ion chromatographic analysis. 相似文献
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应用表面引发原子转移自由基聚合技术(SI—ATRP),以合成的功能单体乙烯基四唑(VT)为单体,以自制的6.0μm单分散大孔交联聚甲基丙烯酸环氧丙酯(PGMA/EDMA)微球为基质,合成了新型弱阳离子交换并具有亲水作用的色谱固定相填料。控制VT单体与引发剂的比率,得到了接枝密度和链长可控的接枝聚乙烯基四唑(PVT)固定相。并考察了聚合反应过程,单体的合成与表征,弱阳离子交换性能、亲水性能等方面。实验结果表明,该色谱固定相色谱性能良好。 相似文献
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We develop the theory for chromatographic separation of isomers such as polycyclic aromatic hydrocarbons, polychlorinated biphenyls, dioxins, steroids, and carotenoids based on shape-selective mechanisms for either exclusion or adsorption. Block-like solute transport and retention on oriented stationary phases are modeled by a dispersed-flow chromatographic equation combined with simultaneous exclusion partitioning and shaped-based adsorption. Molecules to be separated are considered distributed continuously with respect to the shape and sorption parameters. The population balance equations of distribution kinetics provide the governing differential equations that are solved for the temporal moments of the concentration in a chromatographic column. By including dispersive mass transport effects, the model allows estimation of peak variance and HETP and is thus an improvement over theories that focus solely on retention time. The model predictions are compared with experimental data from the literature for gas chromatography. 相似文献