Flow-Cell-Induced Dispersion in Flow-through Absorbance Detection Systems: True Column Effluent Peak Variance,Analytical Chemistry

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Flow-Cell-Induced Dispersion in Flow-through Absorbance Detection Systems: True Column Effluent Peak Variance
Analytical Chemistry ( IF 6.7 ) Pub Date : 2018-01-16 00:00:00 , DOI: 10.1021/acs.analchem.7b04248
Purnendu K. Dasgupta ₁ , Charles Phillip Shelor ₁ , Akinde Florence Kadjo ₁ , Karsten G. Kraiczek ₂

Affiliation

Following a brief overview of the emergence of absorbance detection in liquid chromatography, we focus on the dispersion caused by the absorbance measurement cell and its inlet. A simple experiment is proposed wherein chromatographic flow and conditions are held constant but a variable portion of the column effluent is directed into the detector. The temporal peak variance (σ_t,obs²), which increases as the flow rate (F) through the detector decreases, is found to be well-described as a quadratic function of ¹/_F. This allows the extrapolation of the results to zero residence time in the detector and thence the determination of the true variance of the peak prior to the detector (this includes contribution of all preceding components). This general approach should be equally applicable to detection systems other than absorbance. We also experiment where the inlet/outlet system remains the same but the path length is varied. This allows one to assess the individual contributions of the cell itself and the inlet/outlet system.to the total observed peak. The dispersion in the cell itself has often been modeled as a flow-independent parameter, dependent only on the cell volume. Except for very long path/large volume cells, this paradigm is simply incorrect.

中文翻译：

流通式吸光度检测系统中流通池诱导的色散：真柱流出物峰方差

在简要介绍液相色谱中吸光度检测的出现之后，我们重点介绍由吸光度测量池及其入口引起的色散。提出了一个简单的实验，其中色谱流量和条件保持恒定，但色谱柱流出物的可变部分直接进入检测器。发现随着通过检测器的流量（F）减小，时间峰值方差（σt _，obs²）增大，这被很好地描述为¹ / _F的二次函数。。这允许将结果外推到检测器中的零停留时间，从而确定检测器之前的峰的真实方差（这包括所有先前成分的贡献）。除吸光度外，此一般方法应同样适用于检测系统。我们还尝试了入口/出口系统保持不变但路径长度有所变化的地方。这使人们能够评估细胞本身和入口/出口系统对总观测峰的单独贡献。通常将细胞本身中的分散度建模为与流量无关的参数，仅取决于细胞体积。除了非常长的路径/大体积的单元格外，此范例完全不正确。

更新日期：2018-01-16

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