What Is Paper Chromatography?

Title The Use of Paper Chromatography as an identifier of an unknown Amino Acid complex

Abstract

The purpose of this report is to demonstrate a technique known as Paper Chromatography and it’s effectiveness as a technique for identifying in this case amino acids. The data presented shows that this is not an effective technique for producing accurate results in both calculating the Rf value and in identifying components of a mixture.

Introduction

What are amino acids?

Amino Acids are the building blocks of proteins. Amino acids contain an amino group (-NH2) and a carboxylic acid group (-COOH). Both of these groups are attached to a central carbon. The backbone of an amino acid is made up of three atoms, C-C-N.

The R group varies between different amino acids.

The amino acids being used in this experiment are Lysine, Methionine, Leucine and Aspartic Acid. In biological systems there are twenty amino acids. The four amino acids we are testing for are found within these twenty.

Reference, http://www.sdsc.edu/pb/edu/pharm207/2/lec2.html

What is Paper Chromatography?

Collins (2008,38) states “Paper Chromatography is a technique that separates the components of a mixture according to their solubility in a particular solvent. It is useful when only tiny amounts of each substance are present and may not be detected by one of the biochemical tests. It can also distinguish between substances that give the same result in biochemical tests. For example, the Benedict’s test gives a positive test for both glucose and fructose because both are reducing sugars, but chromatography can separate them easily.”

Collins goes on to state “Different substances dissolve in a particular solvent to different degrees.” The solvent being used in this experiment has been found to be a good solvent for the amino acids being used - (methyl ethyl ketone : propionic acid :water).

Conducting this experiment suggests that specific amino acids can be identified and respective Rf values calculated using the formula

Rf = distance moved by spot

distance moved by solvent front

Collins (2008,38) states , “A particular compound will always have the same Rf value in a particular solvent”.

The aims of this experiment were to

• Distinguish between amino