A Thorough Description of Chromatography

Essay by freespirit01 October 2006

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Introduction

We all know about the processes of Decantation, Evaporation, Sublimation, Extraction etc. All of these chemical processes are considered the basic techniques in performing a scientific research. But there are more techniques aside from the aforementioned processes. This reporting will probe deeper in one: Chromatography. The report has the ff. objectives:

- To let people know about the process of Chromatography

- To demonstrate how a Chromatography Experiment is done and;

- To promote Chromatography as a good and safe experimental technique

This report will focus on 4 important or most commonly used types of chromatography: Paper Chromatography, Column Chromatography, Thin-Layer Chromatography and Gas Chromatography

Definition

Chromatography (from Greek χρώμα: chroma, color) is the collective term for a family of laboratory techniques for the separation of mixtures. It is also one of the members of the broad range of physical methods used to separate and or to analyze complex mixtures.

The components to be separated are distributed between two phases: a stationary phase bed and a mobile phase which percolates through the stationary bed. It is a method for analyzing complex mixtures (such as ink) by separating them into the chemicals from which they are made. Chromatography is used to separate and identify all sorts of substances in police work. Drugs from narcotics to aspirin can be identified in urine and blood samples, often with the aid of chromatography.

History of Chromatography

It was the Russian botanist Mikhail Semyonovich Tsvet who invented the first chromatography technique in 1901 during his research on chlorophyll. He used a liquid-adsorption column containing calcium carbonate to separate plant pigments. The method was described on December 30, 1901 at the XI Congress of Naturalists and Doctors (XI съезд естествоиспытателей и врачей) in St. Petersburg. The first printed description was in 1903, in the Proceedings...