Chromatography

Romero 1
Kate RomerO
Mr. Sousa
Organic Chemistry ACL
8 January 2015
Chromatography
Chromatography is a physical method of separating substances based on their properties, by distributing their components between a mobile and stationary phase. Chromatography is useful for observing mixtures and solvents, since it can be used to determine the relative bond strength of various compounds, a substances phase, and it can also the identity of unknown substances. Chromatography allows for the separation of chemical mixtures, generally in either a gaseous or liquid state, by letting the substance slowly spread past another substance, which is typically in either a liquid or solid state. When chromatography is performed, there is a stationary phase
In the stationary phase, various components of the compound being tested will be adsorbed, and their motion through the mobile phase will cease. The stationary phase acts as a restraint for the components of the substance, and slows them down.
The point at which these components stop moving and separate out can tell information about the compound that can be used to determine the chemical properties of the compound. The speed of the compounds components through the mobile phase is determined by the particles' interactions with the two phases. For instance, the solubility of components in the mobile phase, as well as the measure of their affinities for the stationary phase, will cause certain components to move more quickly than others, which is the basis for their separation. Romero 2
When chromatography is performed, a compound is placed on the stationary phase of the chromatograph. As a substance is introduced, it begins to move, and its molecules adhere to the surface of stationary phase, before being pulled back into the substance. This exchange of molecules is known as adsorption, since the molecules are not permanently attached to, or different way, with some components taking slightly longer than others. The compounds can
It is represented by the letter k”, and can be calculated by dividing the distance traveled by the compound by the distance travefed by the solvent. These numbers can be obtained by measurements, or graphical data.
Chromatography is widely used throughout the scientific community. Gas chromatography is used in forensic pathology because it can efficiently reveal fluids and compounds present in a body after death. It can determine whether the individual had alcohol, poison, or drugs in their system. Paper chromatography can be used to separate and identify different colored pigments in plants. Liquid chromatography is often used to detect pollution in bodies of water. Qualitative chromatography is used to either assign chromatogram peaks to known components, or determine the chemical identity of a sample. Quantitative chromatography may be used when the components are separated and their identities are known.
The goal of quantitative chromatography is to determine the amount of analyte present in the sample, by incorporating math into the