Basic Principles of Chromatography Flashcards
What factors govern how much the stationary phase can attract a particular ion, in ion exchange chromotagraphy?
Ionic radius, Size of valence shell, pH of mobile phase
What are the characterisitics of the materials that can be used in ion exchange chromotagraphy? Give examples
Should contain lots of pores and contain electorstatic charge. Examples include polystrene and polysaccaride based materials with extending OH groups from their backbones.
Describe Partition Chromotagraphy?
Partition chromotagraphy is when sample components are poured through a column with a stationary phase liquid and a mobile phase liquid. The stationary phase liquid will hold certain compounds back depending upon their solubility and polarity while the mobile phase will push certain solutes forward depending upon the same factors
1) Normal phase: Stationary phase is polar and mobile phase is nonpolar. Used to seperate hydrophilic compounds
2) Reversed Phase: Stationary phase is nonpolar and mobile phase is polar. Used to seperate lipophillic compounds.
Describe size chromotagraphy. Ideal Conditions and Non ideal conditions
solvents are poured onto a gel, and the solutes depending upon their size move through the gel pores. If the particles are to big they move around the pores and are eluted first. If the particles are too small they move through the pores and are eluted last.
Ideal conditions: Solutes are not attracted to stationary phase
Nonideal condtions: Solutes are attracted to stationary phase and order of seperation by elution is influenced by other factors
What are the two factors you need to consider when implementing size chromotagraphy
- The size of molecules
2. Purpose for seperation
How do factors like particle size, and diameter affect column seperation and efficiency?
Increase in particle size and diameter decrease column efficiancy as they increase eddy’s diffusion and mass tranfer parameters.
