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Topic: Stationary phase


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In the News (Tue 29 Dec 09)

  
  stationary_phase
The chemical interactions of the stationary phase and the sample with the mobile phase, determines the degree of migration and separation of the components contained in the sample.
The separation of non-electrolytes is achieved by matching the polarities of the sample and the stationary phase and using a mobile phase which possesses a markedly different polarity.
Normal Phase operates on the basis of hydrophilicity and lipophilicity by using a polar stationary phase and a less polar mobile phase.
kerouac.pharm.uky.edu /asrg/hplc/stationary_phase.html   (673 words)

  
 High performance liquid chromatography - Wikipedia, the free encyclopedia
The analyte is forced through a column of the stationary phase in a liquid (mobile phase) at high pressure, which decreases the time the separated components remain on the stationary phase and thus the time they have to diffuse within the column.
Traditionally High Peformence Liquid Chromatography stationary phases were polar, whereas so-called "reversed" phase (RP-HPLC) stationary phases are hydrophobic.
Most tradiational HPLC stationary phases are attached to the outside of silica beads.
en.wikipedia.org /wiki/HPLC   (825 words)

  
 Solid surface texture suitable for a stationary phase for chromatography - Patent 4169790
The apparatus of claim 29, wherein the stationary phase is a physically applied thin film of liquid stationary phase or a stationary phase chemically bonded to the surface of said microvilli.
When a stationary phase is applied to the external surface of the microvilli, the microvilli are preferably enveloped or coated individually so that the surface configuration of the microvilli is retained rather than being completely embedded in a layer of stationary phase.
These or other suitable microvilli serve as a solid stationary phase for chromatography or may be coated at the surface with a continuous or intermittent layer of stationary phase, provided that surface configuration of the microvilli is substantially preserved within the exposed surface of the applied stationary phase.
www.freepatentsonline.com /4169790.html   (5976 words)

  
 Re: Separation techniques including electrophoresis
We are required to select some form of stationary phase, a mobile phase in which to dissolve our materials, and a mechanism to make the solution move.
An examples follows: Stationary phase: paper Mobile phase: water material to be separated: fl marker ink The paper is marked with ink and one end is dipped into the water.
The stationary phase in common use is agarose gel.
www.madsci.org /posts/archives/2000-10/970690139.Mb.r.html   (1201 words)

  
 Chromatography -- Facts, Info, and Encyclopedia article   (Site not responding. Last check: 2007-10-11)
It involves passing the sample, a mixture which contains the (additional info and facts about analyte) analyte, in the "mobile phase", often in a stream of (A liquid substance capable of dissolving other substances) solvent, through the "stationary phase." The stationary phase retards the passage of the components of the sample.
The retention of a compound often differs considerably between experiments and laboratories due to variations of the eluent, the stationary phase, temperature, and the setup.
IMAC is a popular and powerful way to purify (Any of a large group of nitrogenous organic compounds that are essential constituents of living cells; consist of polymers of amino acids; essential in the diet of animals for growth and for repair of tissues; can be obtained from meat and eggs and milk a) proteins.
www.absoluteastronomy.com /encyclopedia/c/ch/chromatography.htm   (1762 words)

  
 ZirChrom Newsletter
Phase II research has also concentrated on the use of phosphonic acid and certain multi-phosphonic acids (see pamidronic acid in Figure 3) as tethering groups for preparing very robust commercial products that are easy to coat and stable under a variety of mobile phase conditions including both normal and reversed-phase.
-Chiral stationary phases incorporate the chemical and mechanical stability of zirconia with the flexibility of renewable Lewis acid/base chemistry chiral modifications.
The influence of end-capping on the enantioselectivity of a chiral phase.
www.zirchrom.com /newsletter.asp   (1448 words)

  
 Chromatography
Chromatography is a separation process that involves partitioning a protein (or any other soluble analyte) between an insoluble stationary phase and a mobile phase that passes over its surface.
If the mobile phase were flowing at a rate of 5 mL/min, then it would take 12 min for the mobile phase to travel from the injector to the detector through the column.
When an analyte of any kind is undergoing chromatography, it is moving at the same rate as the mobile phase when it is in the mobile phase and it is stationary when it is bound to the stationary phase.
www.rit.edu /~pac8612/webionex/website/html/ione8ho9.html   (570 words)

  
 4.2.3 Retention Index and Relative Interactions with Stationary Phase
A polar compound is retained more strongly by a polar stationary phase (and less than non-polar stationary phases), so its RI is larger than one predicts based solely on the number of carbon atoms.
This suggests that the interaction of cocaine with this phase is stronger than the interaction of a non-polar molecule with the polar phase; cocaine is interacting with the phase with an interaction stronger than the dipole-induced dipole interaction expected for an equivalent sized non-polar molecule.
No matter what the stationary phase is, the RI is defined to be 1000 for n-decane, etc. The retention indices of other compounds vary for different stationary phases.
www.dsbscience.com /freepubs/forensic_intern/node33.html   (301 words)

  
 Yeast Genetics of Stationary Phase
Stationary phase, also called the G0 state of the cell cycle, is a remarkable state.
Most of the cells of most microorganisms are in stationary phase most of the time in the wild; the proliferating cell, which has been the object of most studies, is actually a rare state.
Determining the factors responsible for entry into stationary phase, survival of cells in G0, and exit to proliferation is the goal of this project.
www.rose.brandeis.edu /PRLab/projects/yeast/yeast.html   (608 words)

  
 The van Deemter Equation: A Three-Act Play - Act II - Case Study Collection - National Center for Case Study Teaching ...
Partitioning of the solute between the mobile and stationary phases may require more or less time (the equilibration time) depending upon the nature of the stationary phase, the partition coefficient, the diffusion coefficient of the solute in the stationary phase, and other factors.
Stationary phase particles must appropriately arrange themselves across the front of the classroom so as to form a chromatographic column.
Mobile phase molecules will steadily depart from their group, a few at a time, to travel through the "chromatographic column" of stationary phase particles, thereby achieving a constant "flow" through the column.
ublib.buffalo.edu /libraries/projects/cases/vandeemter/vandeemter3.html   (465 words)

  
 [No title]
stationary phase is in a narrow tube 2.
stationary phase is supported on a flat plate or in the pores of a paper 2.
A stationary partition ratio (partition coefficients)- equilibrium constant K=Cs/Cm Cs molar analytical concentration of a solute in the stationary phase.
www.sci.ccny.cuny.edu /~tbandosz/LEC21.DOC   (237 words)

  
 mobile_phase
The chemical interactions of the mobile phase and sample, with the column, determine the degree of migration and separation of components contained in the sample.
For example, those samples which have stronger interactions with the mobile phase than with the stationary phase will elute from the column faster, and thus have a shorter retention time, while the reverse is also true.
The strength of the mobile phase is later increased in increments by raising the organic solvent fraction, which subsequently results in elution of retained components.
kerouac.pharm.uky.edu /asrg/hplc/mobile_phase.html   (700 words)

  
 Chroma2   (Site not responding. Last check: 2007-10-11)
The mobile phase is chosen so as not to react with either the sample nor the stationary phase.
Overall, there is a characteristic affinity of each sample component for the stationary phase, and those components that have a stronger affinity for the stationary phase will remain with it longer and will not be found in the mobile phase as often.
The white and fl balls represent the stationary and mobile phases, while the green balls represent the analyte that moves between the two phases.
www.umich.edu /~orgolab/Chroma/chromahow.html   (313 words)

  
 Chromatographic Identification of Amino Acids
The types of interactions occurring between the solute at the mobile and stationary phases can be classified as follows.
Chromatographic separation techniques are based upon the physical principles of either adsorption and/or partitioning of the solute between the mobile and stationary phases.
            For a particular choice of mobile and stationary phases at a fixed temperature, the distance traveled by a particular solute is constant when compared to the distance traveled by the solvent front (Figure 3).
people.clarkson.edu /~jimbo/2004/controlled.htm   (1896 words)

  
 Chromatography | Types of Chromatography   (Site not responding. Last check: 2007-10-11)
It utilizes a mobile liquid or gaseous phase that is adsorbed onto the surface of a stationary solid phase.
This form of chromatography is based on a thin film formed on the surface of a solid support by a liquid stationary phase.
In this type of chromatography, the use of a resin (the stationary solid phase) is used to covalently attach anions or cations onto it.
www.rpi.edu /dept/chem-eng/Biotech-Environ/CHROMO/be_types.htm   (299 words)

  
 Chromatography   (Site not responding. Last check: 2007-10-11)
Solid-liquid chromatography where the stationary phase is a solid and the mobile phase is a liquid, is the most commonly used (easy to carry out) type of chromatography.
When the mixture is subjected to "chromatography", a partition equilibrium is established by the various components between the two phases namely the stationary phase and the mobile phase.
In column chromatography, the solid stationary phase is packed in a glass column of appropriate dimensions and the mixture containing the components to be separated is applied on top of the packed stationary phase in the column.
www.wiu.edu /users/mftkv/Chemistry102/Chromatography.htm   (694 words)

  
 Lab 5: Chromatography   (Site not responding. Last check: 2007-10-11)
In TLC, the stationary phase is a thin coating of silica (SiO
Silica and alumina are the common choices for the stationary phase because they are very inexpensive.
Now, the stationary and mobile phases are competing for the analyte, and it is very difficult to predict where the spots will end up.
tigger.uic.edu /~shevlin/academics/fall03/lab5.html   (1724 words)

  
 Mutants of Mycobacterium smegmatis impaired in stationary-phase survival -- Keer et al. 146 (9): 2209 -- Microbiology
Mutant strains were grown in Lab-lemco medium plus kanamycin at 37 °C. Viability was assayed by plate counts on entry of the cultures into stationary phase and after 40 d incubation, and the percentage survival over the course of the experiment was calculated.
Strains were grown into stationary phase in Lab-lemco medium plus kanamycin at 37 °C and viability determined by plate counts at intervals during stationary-phase incubation.
Hengge-Aronis, R. The role of rpoS in early stationary phase gene regulation in Escherichia coli K12.
mic.sgmjournals.org /cgi/content/full/146/9/2209   (4366 words)

  
 biology - Affinity chromatography
Affinity chromatography is a biochemical separation method that combines size fractionation capability of gel permeation chromatography with the ability to design a stationary phase that reversibly binds to a known subset of molecules.
Binding to the solid phase may be achieved by column chromatography, whereby the solid medium is packed onto a chromatography column, the initial mixture run through the column to allow binding, a wash buffer run through the column and the elution buffer subsequently applied to the column and collected.
Alternatively binding may be achieved using a batch treatment, by adding the initial mixture to the solid phase in a vessel, mixing, separating the solid phase (by centrifugation for example), removing the liquid phase, washing, re-centrifuging, adding the elution buffer, re-centrifuging and removing the eluate.
www.biologydaily.com /biology/Affinity_chromatography   (772 words)

  
 Stationary Phase Derivation of the Cubic-PM OTF   (Site not responding. Last check: 2007-10-11)
This is the general idea behind the method of stationary phase, first described by Lord Kelvin.
The stationary phase approximation to the magnitude of the ambiguity function of the cubic-pm system is then
The stationary phase approximations are valid for large space-bandwidth product (SBP) functions [9][8].
www.cdm-optics.com /wave/pubs/papers/edf/node6.html   (409 words)

  
 Chem 231 First Homework Assignment   (Site not responding. Last check: 2007-10-11)
In order for solid phase extraction cartridges to work well, the partition coefficient (ratio of compound in the stationary phase to mobile phase) must be large.
It is desired to use a C18 solid phase extraction cartridge to trap compounds A and B, both organic compounds, in order to extract it from a solvent containing 90% water and 10% acetonitrile.
Thus little of compound A will reside in the stationary phase, while most of B will reside in the stationary phase.
www.chem.csus.edu /rwd/Q1sol.html   (424 words)

  
 Technical Report: The Benefits of Ultra-Inert Stationary Phases for the Reversed Phase HPLC of Biomolecules
Chromatographers prefer inert stationary phases for reversed phase HPLC of ionic compounds because they minimize the negative affect of silanols on the separation.
To demonstrate the benefits of ultra-inert phases in biomolecule analysis, several commercially available 300Å pore-size reversed phase columns were tested using three different samples; neutral molecules to measure efficiency, pyridine/phenol to measure silanol activity and antidepressants to measure both silanol activity and metal content.
As shown in Figure 2, the use of 0.1% TFA in the mobile phase enables a column packed with an active stationary phase to give peak widths comparable to those obtained from a new generation column made from ultra-inert stationary phase.
www.mac-mod.com /tr/05031-tr.html   (1231 words)

  
 Adaptation of Mycobacterium smegmatis to Stationary Phase -- Smeulders et al. 181 (1): 270 -- The Journal of ...
Adaptation of Mycobacterium smegmatis to Stationary Phase -- Smeulders et al.
Shleeva, M., Mukamolova, G. V., Young, M., Williams, H. D., Kaprelyants, A. Formation of 'non-culturable' cells of Mycobacterium smegmatis in stationary phase in response to growth under suboptimal conditions and their Rpf-mediated resuscitation.
Kelly, A. F., Park, S. F., Bovill, R., Mackey, B. Survival of Campylobacter jejuni during Stationary Phase: Evidence for the Absence of a Phenotypic Stationary-Phase Response.
jb.asm.org /cgi/content/abstract/181/1/270   (932 words)

  
 The stationary phase approximation
This approximation is known as the stationary phase or saddle point approximation.
The former may seem a little out-of-place, since there is no phase in the problem, but that is because we formulated it in such a way as to anticipate its application to the path integral.
Thus, we can develop a stationary phase or saddle point approximation for the density matrix by introducing an expansion about the classical path according to
www.nyu.edu /classes/tuckerman/stat.mech/lectures/lecture_16/node2.html   (501 words)

  
 ipedia.com: Chromatography Article   (Site not responding. Last check: 2007-10-11)
Chromatography is an analytical chemical process for the separation of mixtures involving passing a sample in the "mobile phase", often in a stream of solvent, through the "stationary phase", some for...
Chromatography is an analytical chemical process for the separation of mixtures involving passing a sample (the analyte) in the "mobile phase", often in a stream of solvent, through the "stationary phase", some form of material that will provide resistance by virtue of chemical interactions (not reactions) between the components of the sample and the material.
In 1952 Archer John Porter Martin and Richard Laurence Millington Synge were awarded the Chemistry Nobel Prize "for their invention of partition chromatography".
www.ipedia.com /chromatography.html   (1009 words)

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