CHROMATOGRAPHY

Last Update 30/ 05/ 2000

in English/ in Esperanto/ in French/ in Portuguese

CHROMATOGRAPHY: several techniques are utilized in this method. Its main objective is to separate substances from a mixture, either with analytical or preparative purposes. It is frequently used in industrial, research and educational laboratories. All the chromatographic techniques utilize a stationary phase and a mobile phase. The stationary phase is formed by a selected material in order to differently retain the components to be separated from the sample. After the migration through the stationary phase for a conveniently selected distance, the components of the sample are separated and accused by the detection system in the sequence: from the first component, less retained, to the last component, more retained, by the stationary phase. The model shown by the above animation represents a chromatographic separation of the letters in the word "cromatografia" (which means chromatography in Portuguese) introduced in a stationary phase in the syringe, where the less retained letter is the first in the alphabet, and the more retained the last. The other letters are retained inside these limits, in alphabetic order. The black coloured diagram is named chromatogram. It represents the peak heights as well, simulating the concentration of the component in the injected sample. The peak height is proportional to the quantity of equal letters in the word.

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Table of subjects.
Presentation
Chemistry Analytical Chromatography
Elemental organic analysis
Volumetric analysis, simulation
Crystallography 3 fold screw axis
4 fold inversion axis on tetrahedron
5 fold rotation axis absent in crystallography
Binary axis and reflection plane in stereographic projection
Bravais lattices
Conic sections under symmetry operators
Converting from spherical coordinates to stereographic projection
Crystal lattice and unit cell
Determination of unit cell
Elements of symmetry in action - animation
Elements of symmetry in action - cube game
Elements of symmetry in action - dodecahedron game
Elements of symmetry in action - icosahedron game
Elements of symmetry in action - octahedron game
Elements of symmetry in action - tetrahedron game
Ewald sphere and crystal measurements
Extinctions
Five classes in the cubic system
Five classes in the rhombohedral system
From tetrahedron to prism
Gnomonic projection
Improper symmetry axis
Miller indices
Miller indices - animation
Miller indices - cube game
Miller indices - octahedron game
Miller indices - rhombic dodecahedron game
Miller indices - tetrahedron game
Mirror plane
Mirror planes and Miller indices game - tetrahedron
Orientations of the cube
p2mm
Plane symmetry groups
Question on point group
Rotation axis in octahedron and Werner compounds
Rotation axis on tetrahedron and organic molecules
Rotation of objects about an arbitrary axis
Rotation of the parallel and stereographic projections of the cube
Rotation of the stereographic and parallel projection of the cube III
Seven faces in stereographic projection
Seven classes in the hexagonal system
Seven classes in the tetragonal system
Six elements of symmetry in seven orientations
Spherical projection of the octahedron
Stereographic projection
Stereographic projection of six polyhedra in different orientations
Straight line equations and symmetry elements
Symmetry, 2 fold axis
Symmetry, 2, 3 and 6 fold axis in benzene
Symmetry, 3 fold axis in the cube
Symmetry, 4 fold axis in the cube
Symmetry, 4 fold axis in the unit cell of gold
Symmetry elements and Miller indices game
Symmetry elements and Miller indices game - octahedron
Symmetry in art and in crystallography
Three classes in the monoclinic system
Three classes in the orthorhombic system
Twin crystals
Two classes in the triclinic system
Unit cell in hexagonal net
General Butane conformations
Density
Electrochemical cell
Ethane conformations
Oxidation and reduction
Resources of chemical-ICT: water, health and symmetry
Solid and liquid gold