what are conditions necessary for a substance to be separated by chromatography(paper chromatography)?
816465
Two substances must flow through the medium at different rates. High performance liquid chromatography operates by running a liquid through a solid column. The molecules with the same chemical properties as the solid will take longer to go through the column. If the solid is polar and the liquid is non-polar, then non-polar molecules will move through faster because they do not get stuck in the solid. Bead chromatography involves running a liquid through a column loaded with gel beads that contain some holes. Smaller molecules spend some time in the holes, but molecules too large to enter the holes go straight past the beads and exit the column first. There are different ways to separate substances and there are a ton of different chromatography methods.
951472
Longer the column better resolution you can get during separation. And wider one might do same. It's the surface contact with compound and silica used for chromatography. And adding pressure to it help increase total area of surface contact.
919511
Chromatography is used mainly to quantify or measure purity and the concentrations of impurities present in a sample.\n\nTLC is used to used in many Quality Laboratories to measure the impurities present in raw materials.  Most amino acids, along with some other active pharmaceutical ingredients, used in the pharmaceutical/biotechnology industry require impurity testing by TLC.
180398
It varies depending whether you want the final product as an active protein or denatured.\n\nFrom cells\n\nHomogenisation\nCentrifugation (assuming you know what fraction the protein will be in)\n\nYou could then possibley use centrifugation across a glucose gradient that would further separate proteins or more simpley...\n\nFind a pH or temperature where the protein is insoluble. (Extremes will denature the protein)\nor...\nUse a size exclusion coloumn to filter out larger smaller proteins (depending on the coloumns specifications and your needs, won't denature).\n\nFor further purification:\n\nUse isoelectric focusing across a gel.\nUse a affinity chromatography coloumn specific to your protein.\n\nHope that helps. It's from memory and should be ok, I study biochemistry so if I've things wrong then I should be quite worried!
796763
See the links at the reference given.\n\nHPLC is a popular method of analysis because it is easy to learn and use and is not limited by the volatility or stability of the sample compound. The history section illustrates the HPLC's evolution from the 1970's to the 1990's. Modern HPLC has many applications including separation, identification, purification, and quantification of various compounds. It is important for those using HPLC to understand the theory of operation in order to receive the optimum analysis of their compounds. For those interested in purchasing or using an HPLC we have included a list of manufacturers, a troubleshooting guide, technical assistance, and a bibliography to help reduce your personal research and referencing time. Once you have completed the theory of operation, you will be qualified to take a quick quiz to test your understanding of HPLC systems.
41955
when your body makes/separates a substance. Example: stomach acids, semen, mucus, etc.
150817
What Is It??\nHello, everyone, and welcome to the wonderful world of chromatography! What is chromatography, you ask?? Well, quite simply, it is a broad range of physical methods used to separate and or to analyze complex mixtures. The components to be separated are distributed between two phases: a stationary phase bed and a mobile phase which percolates through the stationary bed. \n  \n  \nHow Does It Work? Like Magic!\nA mixture of various components enters a chromatography process, and the different components are flushed through the system at different rates. These differential rates of migration as the mixture moves over adsorptive materials provide separation. Repeated sorption/desorption acts that take place during the movement of the sample over the stationary bed determine the rates. The smaller the affinity a molecule has for the stationary phase, the shorter the time spent in a column.
516829
Preparative HPLC should do the trick.  Try a search at these to see if an exact procedure might be on the web.\n\n\nhttp://www.scienceresearch.com/search/\n\nhttp://www.scirus.com/srsapp/
336109
Freezing only works on a certain percentage mixture.  Chromatography on regular phase silica would work the best using a non polar hydrophobic solvent.
151863
Either:\n\n(a) you're not getting a very clean separation, as the peaks should be vivid\n\nor\n\n(b) your detector is insuitable for the acids you're studying.\n\nAtleast, that's my analysis. Any A-Chem experts here?
37898
I worked with HPLC starting in th days when it was called High Pressure instead of High Performance LC.  I used several chromatographs over a five or ten year period.  It is basically a column chromatograph which is scaled down and uses a pump to move the mobile phase.\nThere are some nice sites which can give you the basics.  In addition there is an on-line forum for asking questions.
409824
When what is mixed is not fully disolved into the liquid medium.  It usually settles.  A cenrifuge will not separate out the components that are not part of the solution.
738985
physical methods of separation; distillation, filtration, centrifugation, etc.\nChemical methods: sublimation, crystallization,  chromatography (actually, a combination of the chemical properties of the solubilty of the item in solution, and physical separation of stubstances via filter paper)
955885
In column chromatography, the elution of analytes is a function of both the stationary and mobile phases (among others things, like temperature).\n\nIf the analyte does not elute, then either the stationary or mobile phase was not chosen correctly.  K' might be very large without being infinite.  The compound may be moving through the column, but too slowly to elute entirely from the column.\n\nFor example:  if the stationary phase is silica gel and the compound does not elute with alcohol or water, then a basic or acidic aqueous solution might be needed to elute the compound.
127488
Their difference in polarity and density are probably the two most likely properties to affect the rate of separation. Molecular weight differences between the two liquids would probably have some impact, also temperature would effect the rate of separation.
765881
The liquid should be clear...litmus paper is white usually...turns pink to red when in an unbalanced PH soulution....Yukoneze
759502
Breakdown into separate phases of a relatively stable emulsion, by such means as flocculation with a surface-active agent or removal of an emulsifying agent.