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Chromatography
Published in Pau Loke Show, Chien Wei Ooi, Tau Chuan Ling, Bioprocess Engineering, 2019
Kirupa Sankar Muthuvelu, Senthil Kumar Arumugasamy
The characteristic rate equation that illustrates the chromatographic separation efficiency depending various physical column parameters is known as the Van Deemter equation. It incorporates the kinetic theory of chromatography to relate the migration and dispersion of solute bands through a column packed with spherical particles in a constant mobile phase flow. The goal in understanding the separation process is to enhance column efficiency by understanding how to reduce band broadening. Several parameters have been highlighted in the Van Deemter equation for a chromatographic run that can be manipulated to reduce band broadening. According to the Van Deemter equation, band broadening may happen for the following reasons: An analyte can take multiple paths to travel through the packed materials in a columnMolecular diffusionMass transfer effect between phases
Capillary Electrophoresis
Published in Grinberg Nelu, Rodriguez Sonia, Ewing’s Analytical Instrumentation Handbook, Fourth Edition, 2019
The separation efficiency of CE and other chromatographic high-resolution techniques is described by the van Deemter equation, which relates the plate height, H, to the velocity, νx, of the carrier gas/liquid along the separation axis, x, where A, B, and C are constants. The van Deemter equation is given in Equation 25.1:H=A+B/νx+Cνx
Factors affecting therapeutic protein purity and yield during chromatographic purification
Published in Preparative Biochemistry & Biotechnology, 2023
Che Haznie Ayu Che Hussian, Wai Yie Leong
An acceptable column diameter and bed height are also required to provide adequate separation of proteins.[27] This reduces the pressure difference across a single segment of the column, allowing smaller particles and nonrigid gels to be used to improve resolution. This enables proteins to be separated easily in the column system, resulting in a high yield. The uniform flow distribution in column bed packed was very difficult to achieve, which led to peak broadening and had an impact on purity, recovery, and productivity. Therefore, recently researchers have begun to experiment with cuboid bed-packed chromatography.[28] Several papers have described and examined the application of this cuboid bed packed. The image below in Figure 2 depicts two columns with the same column volume but varying bed height and column diameter, which affects protein separation resolution since higher length/diameter ratios yield a greater resolution. Based on the van Deemter equation, the height equivalent to a theoretical plate (HETP) obtained with a cuboid-packed bed device showed a significantly lower value compared to a bed-packed column when both were operated at the same superficial velocity, explaining that better resolution and separation were obtained in cuboid bed packed. Table 1 shows several purification studies conducted using cuboid bed packed with different chromatography methods, (ion exchange chromatography and affinity chromatography), and they also use the same resins. The majority of studies found that cuboid bed packing improved protein separation significantly compared to column chromatography.
New inverse gas chromatographic methodology for studying mass transfer caused by the evaporation of volatile liquids
Published in Instrumentation Science & Technology, 2019
Kosmas Martakidis, Dimitrios Gavril
Gas chromatography (GC) has been utilized for extracting mass transfer coefficients[3,4] since the introduction of peak broadening factors, by the Van Deemter equation,[5–7] which relate the separation capacity of the chromatographic column to various flow and kinetic parameters. Reversed-flow inverse gas chromatography (RF-IGC) allows the determination of physico-chemical measurements. It is named by the initial reversing of the carrier gas flow, which permits the sampling of the physico-chemical processes taking place between the injected solute and the stationary phase. Moreover, the studied processes are not affected by the carrier gas flow.