it is a broad range of physical methods used to separate and or to analyze complex mixtures.

Chromatography Made Easy

Take this lab we did in Biology 2...

We took a coffee filter, acting as chromatography paper, and drew 3 small dots on the paper, in different colors. Then we soaked the bottom of the strip in ethanol, and watched as the colors began to "bleed" up the strip of paper.

Types of Chromatgraphy

Gas Chromatography: Gas chromatography is a chromatographic technique that can be used to separate organic compounds that are volatile. A gas chromatograph consists of a flowing mobile phase, an injection port, a separation column containing the stationary phase, a detector, and a data recording system. The organic compounds are separated due to differences in their partitioning behavior between the mobile gas phase and the stationary phase in the column.

Liquid Chromatography: There are many different types of liquid chromatography.

There is liquid adsorption chromatography in which an adsorbent is used. This method is used in large-scale applications since adsorbents are relatively inexpensive.

There is also liquid- liquid chromatography which is analogous to gas-liquid chromatography. The three types that will be considered here fall under the category of modern liquid chromatography.

Size exclusion chromatography, also known as filtration chromatography, does not involve any adsorption and is extremely fast. It is capable of separating large molecules from smaller ones. This method is common in protein separation and purification.

Ion Exchange Chromatography: Ion exchange chromatography is commonly used in the purification of biological materials.

There are two types of exchange:

Cation exchange in which the stationary phase carries a negative charge &

Anion exchange in which the stationary phase carries a positive charge.

Charged molecules in the liquid phase pass through the column until a binding site in the stationary phase appears. The molecule will not elute from the column until a solution of varying pH or ionic strength is passed through it. Separation by this method is highly selective. Since the resins are fairly inexpensive and high capacities can be used, this method of separation is applied early in the overall process.

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