Posts

Showing posts with the label chromotography

HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

Image
 HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY It is a method used for the separation, purification, and identification of various nonvolatile high molecular weight organic compounds and natural products like cholesterol, terpenoids. ADVANTAGES High-speed separation Excellent column separation Solvent consumption is minimum Sensitive and accurate Separation can be done at an ambient temperature. PRINCIPLE The components of the mixture are separated depending upon the extent of adsorption and partition on the stationary phase and the rate at which the component is carried by the mobile phase. The mobile phase is liquid and the stationary phase can be solid or liquid. INSTRUMENTATION Solvent reservoirs are used to collect the different solvents. Pressure pump to apply pressure  Sample injector to give the mixture which is to be separated in the analytical column Regulator to adjust the flow rate Guard column to remove the particulate matter and contaminants from the solvent. The analyt...

THIN LAYER CHROMATOGRAPHY

Image
 THIN LAYER CHROMATOGRAPHY It is a chromatographic separation method used to separate mixtures, to check the purity of a mixture, and to monitor the progress of the reaction. Procedure A glass plate coated with a material of the adsorbent will constitute the stationary phase. The material is made into a slurry or a paste and the glass plate is coated with it by a thin layer applicator and dried. This glass plate with a thin layer of stationary phase is called chromatoplate. The mixture to be separated is applied to one end of the plate and it is placed in the solvent. When the solvent reaches near the top, it is removed and dried. If the components are colored the spots can be readily located. If the components are colorless the dried plate is sprayed with a suitable reagent to make the spot colored. In this way, the position of the components is located and their Rf values are determined. Rf value is the ratio of the distance traveled by a component to the distance traveled by the...

CHROMATOGRAPHY

Image
CHROMATOGRAPHY  It is a method used for the separation, purification, and identification of a mixture of substances. It is useful when components of a mixture have similar physical and chemical properties and hence cannot be separated by other methods. Principle: It is based on the distribution of the components in a mixture between a stationary and a mobile phase. The stationary phase may be a column of adsorbent, a paper, a thin layer of adsorbent through which the mobile phase moves on. The mobile phase may be a liquid or gas. The principle of chromatographic separation is always adsorption (absorption of a constituent on the surface of the solid stationary phase) or partition (distribution of a constituent in between two liquid stationary phases). THEORY OF CHROMATOGRAPHY The separation takes place due to the differential migration of components which depends on the relative affinity towards the stationary and mobile phases.  The component which is less strongly held by th...