Chromatography Flashcards
What is chromatography
A laboratory technique used for separating a mixture all types of chromatography based on a very simple concept the sample to bed assignment is allowed to interact with to physically distinct entities a mobile phase and a stationary phase the molecules targeted for analysis are called
Mobile phase
Can be either liquid or gas moves the sample components through the region containing the solid or liquid stationary phase called the solvent
Stationary phase
Has the ability to bind some types of analytes and this varies from one chromatography method to another analyse data preferentially bound by solvent are observed to be retarded in their movement through their chromatographic system molecules that show week affinity for the sub and spend more time in the mobile face in the more easily removed or eluted from the system
Development
The general process of moving a sample mixture through chromatographic system is called development
Mobile phase
Substances to be separated and mixed with this fluid it may be gas a liquid it continues to move through the chromatographic instruments
Stationary phase
It does not move it is packed inside a column it is a porous matrix that helps separate the substances present in the sample it works in accordance with the simple physical process called adsorption
Types of chromatographic methods
Paper and thin layer chromatography gas chromatography liquid chromatography gel filtration chromatography ion exchange chromatography affinity chromatography
Paper and thin layer chromatography
An example of partition chromatography due to similarities in the theory and practice of these two procedures they are considered together this type of chromatography may be applied to two major types of problem identification of unknown samples and the isolation of the components of a mixture in paper chromatography the cellular support is extensively hydrated so that the distribution of the underlined or clause between the immobilized servant and the mobile developing soap and solvent in thin layer chromatography the initial stationary liquid phase is the solvent used to separate the thin layer of absorbent however as the developing solvent molecules move to the solvent polar solvent molecules made by into the immobiliser port and become sorbent
Applications of planar chromatography
Forensic science
Retention factor
In millimetres to decimal places distance moved by spot / distance moved by solvent
the larger the RF value the most soluble the smaller the RF value the less soluble solvent also known as eluting solvent is equal to mobile phase
