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1.
推导了密度线性程升时超临界流体色谱中保留值的运动方程和相应的理论板高方程式, 并在超临界色谱条件下用毛细管柱和微填充柱上的数据对保留值方程作了验证, 理论计算值和实验测量值之间的偏差最大不超过5.00%。在推导理论方程时,设一定密度范围内1nk和密度p之间为线性函数, 这个假设也得到了实验验证。  相似文献   

2.
推导了密度线性程升时超临界流体色谱中保留值的运动方程和相应的理论板高方程式,并在超临界色谱条件下用毛细管柱和微填充柱上的数据对保留值方程作了验证,理论计算值和实验测量值之间的偏差最大不超过5.00%.在推导理论方程时,设一定密度范围内lnk和密度ρ之间为线性函数,这个假设也得到了实验验证.  相似文献   

3.
色谱保留值方程的统一形式   总被引:1,自引:0,他引:1  
本文采用点阵模型,运用统计热力学方法推导出色谱保留值方程的统一形式。根据不同的条件从此统一形式可获得描述气-固色谱、气-液色谱、液-固色谱、液-液色谱以及超临界流体色谱保留值规律的方程。上述方程均采用实验数据予以验证。  相似文献   

4.
从分子微观参数预测反相色谱保留值方程系数   总被引:8,自引:1,他引:7  
戴朝政 《色谱》1995,13(2):75-79
在考虑氢键作用能随流动相组成改变的情况下,重新推导了液相色谱保留值方程,进而得到液相色谱保留值方程系数与分子微观参数之间的关系。在分子母体结构相同条件下,提出采用五个系数预测反相色谱保留值的方法,并用文献数据给予验证。  相似文献   

5.
戴朝政  李浩春  卢佩章 《色谱》1988,6(5):259-262
]超临界流体色谱(SFC)是色谱领域内的一项新技术。本文导出了SFC保留值与柱温、流动相密度(ρm)的关系为:Ink'=a+b/T-cρm2/T+dρm2.6上述方程是运用统计热力学方法推导出来的。借用文献发表的数据,在色谱实际应用范围内验证了此式。  相似文献   

6.
边六交  耿信笃 《色谱》1996,14(3):179-181
通过考虑溶质和溶剂在液相色谱体系中的相互作用,从理论上给出了一个描述溶质在液相色谱体系中进样量与保留值之间关系的方程。由方程可以证明,当进样量趋于零时,溶质的保留值为一定值,当进样量无限大时,溶质的保留值趋于零,且随着进样量的增加,溶质的保留值必然减小。通过方程的线性形式,可以获得两个描述色谱体系特征的重要参数:一个是溶质与固定相相互作用的平衡常数K,另一个是假想的分布在固定相表面上的活性点总数。  相似文献   

7.
本文在 Martire 等人以平均场晶格模型处理超临界流体色谱(SFC)保留值方法的基础上,提出修正函数的假设,结合实验数据确定了修正函数的具体表达式为△′=(0.01605+0.02387n_■)ρ~3_■/T,-(0.01382+0.02055n_■)ρ~4_■/T_■。经过修正后的保留值方程可在较大密度范围内(ρ_■:0.705~1.632)定量描述正构烷烃在非极性柱上,超临界流体 CO_2中的保留值变化规律。  相似文献   

8.
用色谱保留值法测定了单质碘和单斜硫在不同温度及压力下在超临界二氧化碳中的溶解度,并用超临界平衡饱和萃取法验证了测定值,结果满意。  相似文献   

9.
焦庆才  于如嘏 《分析化学》1993,21(12):1392-1398
根据热力学原理和简单的吸附色谱分子模型。本文提出了一个新的液固色谱保留模型,并导出了相应的保留值基本方程,以三元溶剂系统作为展开剂,用薄层色谱实验数据验证了所得方程的正确性。结果显示,计算Rf值与实验Rf值完全一致。  相似文献   

10.
反相高效液相色谱中溶质保留值与流动相组成关系的探讨   总被引:2,自引:0,他引:2  
汪小江  王连生  田笠卿 《色谱》1992,10(2):70-74
]本文采用分配理论和共溶剂理论的方法,探讨了反相高效液相色谱中溶质的保留机制,并推导了溶质保留值与流动相组成的关系式。利用该关系式计算溶质的保留值,所得结果与实验值基本吻合。  相似文献   

11.
Summary It has been known for almost 20 years that in practice the widths of peaks eluted isothermally from a capillary column working under good conditions increase linearly with increasing retention time. The use of this plot, following the ABT-concept, to derive useful data to express the quality of capillary columns is challenged. The ordinate intercect of the plot results from the column contribution to the band broadening of a non-retained peak, which is easy to predict from the Taylor-Golay equation, and from the equipment contribution. With modern instruments it is easy to keep that second contribution to a reasonably low value for 0.25 mm i.d. columns. The first cannot be reduced to zero as claimed by some authors. Furthermore the two contributions are additive, following the variance addition rule. Consequently the peak width versus retention plot is no longer linear when the equipment contribution becomes large. These facts make the so-called ABT-concept seriously misleading. Other rules derived from practical experience and sound theoretical considerations are given for checking capillary columns.  相似文献   

12.
本文提出了智能最佳化气相色谱柱温的理论基础, 解决了最佳温度求解区间及控温方式的预测、 最难分离物质对及交叉点的预测、围绕最难分离物质对及交叉点的最佳化分离温度的预测三个问题, 为智能最佳化柱温程序奠定了基础。  相似文献   

13.
以硫脲作为电渗流标记物测定的死时间和以苯同系物线性回归方法测定的死时间为基础,将液相色谱中溶质保留值方程应用到电色谱中,得到了容量因子与二元流动相体系中有机改性剂含量之间的关系曲线;通过实验数据说明了一些极性的电中性化合物在电场作用下也会发生迁移而引起保留值的变化,且这种变化还受有机改性剂含量的影响。  相似文献   

14.
Summary The application of capillary SFC for SIMDIST investigations of paraffins and waxes is reported. Pressure, density and temperature of the mobile phase are optimized to obtain high chromatographic resolution of complex mixtures of industrial products. Isothermal linear pressure programming and asymptotic pressure and density programming are used in the range from 15 to 35 MPa in the isothermic mode above 100°C. SFC chromatograms of natural and synthetic paraffins, microcrystalline wax and candle wax are compared. The retention behaviour of paraffin mixtures and waxes has been investigated on methyl/phenyl and biphenyl capillary columns. The polarity of the stationary phases influences the absolute retention time more than it influences the chromatographic resolution.  相似文献   

15.
Once a suitable stationary phase and column dimensions have been selected, the retention in liquid chromatography (LC) is traditionally adjusted by controlling the mobile phase composition. Solvent gradients enable achievement of good separation selectivity while decreasing the separation time as compared to isocratic elution. Capillary columns allow use of other programming parameters, i.e. temperature and applied electric fields, in addition to solvent gradient elution. This paper presents a review of programmed separation techniques in miniaturized LC, including retention modeling and method transfer from the conventional to micro- and capillary scales. The impact of miniaturized instrumentation on retention and the limitations of capillary LC are discussed. Special attention is focused on the gradient dwell volume effects, which are more important in micro-LC techniques than in conventional analytical LC and may cause significant increase in the time of analysis, unless special instrumentation and (or) pre-column flow-splitting is used. The influence of temperature upon retention is also discussed, and applications where the temperature has been actively used for retention control in capillary LC are included together with the instrumentation utilized. Finally the possibilities of additional selectivity control by applying an electric field over a packed capillary LC column are discussed.  相似文献   

16.
本文在作者提出的反相液相色谱中同系物保留值与常沸点的交点规律基础上,推导出系物保留值与流动相组成的交点规律,用大量实验数据作了检验。并用新交点方程式,由化合物在一个流动相组成下的保留值,预测该化合物在任一流动相组成下的保留值,对14组同系物在5种色谱柱上5类流动相下的验算结果表明,721个数据点的绝对平均误差为2.8%。  相似文献   

17.
The technique of programming the carrier gas flow rate in gas chromatography, especially in connection with the use of capillary columns shorter than 10 m can significantly accelerate GC analyses. Equations for calculation of the parameters of the exponential flow function and retention data are described. The effects of flow programming in a short capillary column are shown in a few chromatograms. Different programming rates are tested and compared with temperature programming.  相似文献   

18.
Summary Effects of column temperature on the retention behaviour of aromatic hydrocarbons and dialkyl phthalates were investigated in capillary supercritical fluid chromatography (SFC) with carbon dioxide as the mobile phase. Negative temperature programming could partly replace pressure programming. Positive temperature programming was applicable to solutes with proper volatility, in which gas chromatography-like retention mechanism (partition process) was involved.  相似文献   

19.
通过对色谱分离过程的热力学处理, 得到了用毛细管色谱法测定溶质在溶剂中的溶解热力学性质的关系式, 利用该式测定了硝基氨基甲苯的五种异构体在SE-30, SE-54固定液中的溶解焓和溶解熵, 并对结果进行了定性解释。  相似文献   

20.
通过对色谱分离过程的热力学处理,得到了用毛细管色谱法测定溶质在溶剂中的溶解热力学性质的关系式,利用该式测定了硝基氨基甲苯的五种异构体在SE-30,SE-54固定液中的溶解焓和溶解熵,并对结果进行了定性解释。  相似文献   

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