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Chromatography

Chromatography is a set of techniques used to separate mixtures in a chemistry lab setting. The word chromatography means "color writing" and some of the first experiments in chromatography involved separating chlorophyll in plants.

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Organic Chemistry
Chromatography

What is a meniscus in chemistry?

A meniscus is the gentle curve displayed at the top of a liquid when it is poured into a container.

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Chemistry
Chromatography

Meaning of funnel separation?

It is a way in separating mixture where they are using funnel and filter paper in separating

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Chromatography

What are the apparatus for paper chromatography?

the apparatus are:petri dish , solvent such 3 parts of water and 1 part of methanol,thin paper ,samples either liquids samples or magic samples

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Chromatography

Factors affecting Gas Chromatography?

- Temperature ramp rate

- Column length

- Carrier gas flow rate

- Film thickness

- Column internal diameter

- Ultra fast technology

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Chromatography

What are the advantages of paper chromatography over thin layer chromatography?

It's less expensive to perform, and you can do "two way" chromatography by running a chromatograph in one solvent, letting the paper dry, turning it 90 degrees and running a second chromatograph in a different solvent. Many times paper chromatography

is used to visualize separate components of a solution. The separation can be based on molecular weight, size, structure, etc. It can be used to determine what exactly is present within a solution.

Thin layer chromatography is faster and more accurate, so it's more popular now.


The principle between the two are the same, but each is different. Here's five ways they differ:

1. TLC uses a different stationary phase than paper chromatography (paper is the stationary phase in the latter while TLC usually uses silica or alumina as the stationary phase).
2. TLC gives better separations than paper chromatography, that is, bands that are sharper and further spaced out.
3. TLC is faster to run.
4. TLC requires fewer samples to work effectively.
5. TLC has better selectivity (things it can separate). One

can use different kinds of absorbents (stationary phases) with TLC, which gives more flexibility in separating different kinds of chemicals. TLC plates can also withstand stronger solvents and color forming agents than paper chromatography, so again it is more flexible (stronger solvents can speed up the process and introduce more selectivity to the separation).

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Chromatography

How do police use chromatography?

Chromatography is the most used separation-technique in forensic-chemistry and forensic-toxicology. HPLC and thin-layer-chromatography are often used to analyse samples of blood and urine to search for drugs and toxines as well as to search for toxines in case of a murder or an unexplained death. To identify and quantify a unkown toxine chromatography is mostly combined with mass-spectrometry. But in case of searching for heavy-metals methods of atomic-absorption-spectrometry are more often used instead of chromtography.Gas-chromatography in connection with FID and headspace-analysis is a common technique to quantify the amount of alcohol in a blood-sample.

At least the technique to analyse DNA-samples called "Gel-Elektrophoresis" is also a chromatography-technique.

To analyse paints of faked paintings or documents or car paints in case of an accident or crimes, the IR-spectrometry is the more common technique, it would also be possible to analyse these samples by thin-layer-chromatography or other chromatography-techniques, but IR-spectrometry is more reliable.

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Chromatography

How does chromatography work to separate particles?

Column chromatography is a separation technique in which the stationary bed is within a tube. The particles of the solid stationary phase or the support coated with a liquid stationary phase may fill the whole inside volume of the tube (packed column) or be concentrated on or along the inside tube wall leaving an open, unrestricted path for the mobile phase in the middle part of the tube (open tubular column). Differences in rates of movement through the medium are calculated to different retention times of the sample.

In 1978, W. C. Still introduced a modified version of column chromatography called flash column chromatography (flash). The technique is very similar to the traditional column chromatography, except for that the solvent is driven through the column by applying positive pressure. This allowed most separations to be performed in less than 20 minutes, with improved separations compared to the old method. Modern flash chromatography systems are sold as pre-packed plastic cartridges, and the solvent is pumped through the cartridge. Systems may also be linked with detectors and fraction collectors providing automation. The introduction of gradient pumps resulted in quicker separations and less solvent usage.

In expanded bed adsorption, a fluidized bed is used, rather than a solid phase made by a packed bed. This allows omission of initial clearing steps such as centrifugation and filtration, for culture broths or slurries of broken cells.

Phosphocellulose chromatography utilizes the binding affinity of many DNA-binding proteins for phosphocellulose. The stronger a protein's interaction with DNA, the higher the salt concentration needed to elute that protein

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Chromatography

What is Rf value?

It is the distance travelled by the sample or analyte divided by distance travelled by the solvent front in chromatography.

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Chromatography

How did the name chromatography originate?

The name Chromatography is coming from the Greek "Chromos" ("colour") and "grafein" (" to write") so chromatography is "writing with colours". This refers to the first chromatographic experiments with plant pigments were the sample was put on a filter paper, dried and the separation obtained by dropping "eluans" on it so that concentric (at that time only coloured) rings were formed

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Chromatography

Examples of desirable and undesirable?

Desirable: Dog, cats, horses (any animal) and other great things

Undesirable: Nasty, wretched, and vile things

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Chromatography

Does the total number of moles reactants necessarily equal the total number of moles of product?

Absolutely not. Chromtagraphy is qualitative, not quantitative. cheers

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Chromatography

Does chromatography show a chemical or physical change?

Chromatography is simply a process used for separating chemicals that were mixed together, into different locations (on a strip of paper, or other absorbent material) hence, it is a physical change, not a chemical change.

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Animal Life
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Technical Writing
Chromatography

Example for writing of test scenario?

EX:Login page In login page you have to give values for user name, password and then click on ok button to login and cancel button to close the login window user name:Alphanumerics with 4-16characters long password:lowercase letters with 4-8 chars long OK :Next window CANCEL :Close the window Prepare Test Scenarios Test Scenario Template --------------------------- Test scenario1:Verify user name value Test Scenario2:verify pass word value Test Scenario3:verify OK button operation to login Test Scenario4:verify cancel button operation to close the window Ts1:Verify user name value a)Boundary value analysis (on Size) min=4characters maximum=16 characters more than max or less than min are not allowed b)Equivalence class partitions(on type) A-Z or a-z or 0-9 are valid types to be entered special symbols or blank fields are in valid Test Scenario2:verify pass word value SAME AS USER NAME Test Scenario3:verify OK button operation to login Decision table user name ------pass word-----expected outcome after click on "OK" valid valid next window valid invalid error message invalid valid error message blank value error message value blank error message Test Scenario4:verify cancel button operation to close the Decision table user name ------pass word-----expected outcome blank blank close the window value blank close the window blank value close the window value value close the window Like the above example we will write test scenarios for all the Functional Specifications.

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Chemistry
Acids and Bases
The Difference Between
Chromatography

What is the difference C8 and C18 HPLC Column?

Both C8 and C18 columns are considered as examples of reversed phase liquid chromatography (RP). The stationary phase here is seen as a thin film of non-polar liquid phase that has been designed to be chemically anchored to an inert material (Silica gel particles). The non-polar layer is chemically linked to the silica particles surface by reaction with the polar silanol groups on the stationary phase surface and so rendering them (less polar or non-polar), The difference between the two columns will be in the length of the carbon-chain attached to the silica surface. Acoordingly C8 hplc columns have packing material composed of silica particles attached to C8 carbon units while C18 will, of course, have packing materials coated with C18 hydrophobic units. Categorically both are reversed phase but C18 columns will definitely be more "hydrophobic rather than the C8 columns.

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Chromatography

How does chromatography important in daily life?

Chromatography is used to test your everyday products you use and enjoy. The products tested is your food. Chromatography tests a sample of your food back in the laboratory to see if it is clean and un-contaminated. Once the Chromatogrpahy shows no contamination then your food is sent to the stores so you can buy it.

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Chromatography

Is gas chromatography reliable?

yes.


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Chromatography

Why is process of chromatography benefit to humans?

It can help in the purification of substance that are soluble in any solvent and also this helps because every substance has a different retention factor so they will all appear on different levels in the chromatogram this is used in the field of medicine to obtain extremely pure chemicals for the production of drugs.

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Chromatography

What is the conclusion of the ink chromatography?

Conclusion: the dyes found in {substance being separated} were {components found}. the corresponding Retention factor are...................

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Chromatography

What happens in paper chromatography in inorganic ions?

Migration of any species in a chromotography plate/paper is regulated by the solvent. Beyond that, your question has no answer because it does not actually mean anything.

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Chemistry
Chromatography
Pens and Pencils

Why is the pencil used in drawing a line in paper chromatography and not a ball pen?

Because the ink from the pen will run and smear during the chromatography but the pencil mark is not affected.

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Genetics
Crime
Chromatography

How is DNA used to catch a criminal using chromatography?

Each persons DNA is different... even twins. When you put DNA in a HPLC you will be able to find the certain characteristics of DNA and match it to any persons DNA you already have in your system.

When using chromatography you have computer software. In that software you can keep a library of certain samples. Lets say you have a criminal and you have his DNA. Lets say he commits a crime and you need to prove that he did it. Well you can match the DNA from the crime scene that is his and put it through the HPLC. The HPLC will then match the crime scene DNA with the DNA you have stored in your software.

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Biology
Chromatography

What happens to water molecules when they are heated?

Like all molecules, a molecule of H20 is in constant motion; 'hot' molecules move faster than 'cold' molecules. If the molecules move slowly enough the substance appears stationary to us (frozen water) and if they move quickly enough they will expand to fill their container (vapor or gas water.)

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Chromatography
Metal and Alloys

Is chrome plating porous?

leedle leedle leedle lee

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Science Experiments
Chromatography

Why is acetone used in paper chromatography?

Because permanent inks are acetone soluble.

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Organic Chemistry
Periodic Table
Chromatography

Notes of class inter chemistry in English?

Taking notes is a great way to help students identify the importance of concepts covered in class. Even if you have a great memory, you simply won't be able to remember everything the teacher says. A permanent written record that you can refer to later can prove indispensable when it's time to write an essay or take a test on the materials discussed in class. If anyone want to get intermediate chemistry notes here you can find https://www.beeducated.pk/notes

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