Stationary and Mobile phase

Paper and Thin layer chromatography (TLC) Separates components in a mixture and can be used to identify what components make up a mixture. Stationary phase is a thin layer of polar silica PAPER CHROMATOGRAPHY Separates components in a mixture that are coloured. Stationary phase is paper The mobile phase for both was Butan-1-ol:Ammonium hydroxide: Ethanol 6:2:2

The different phases of chromatography STATIONARY PHASE – A solid surface on which a component ADSORPS on to and a mobile phase runs through. MOBILE PHASE – The phase which moves up the paper/silica plate carrying the components in a mixture up the plate and separates them.

Adsorption - the adhesion (stickyness) of a chemical species onto the surface of particles. Absorption – When atoms, molecules or ions enter the bulk material of something.

Be able to explain the two factors which affect how a components moves through the mobile phase.

Polarity What is the definition of a polar molecule? - Think-pair-share (2 minutes) A polar molecule is one with a partial negative charge on one end and a partial negative charge on another end – A charged molecule

Intermolecular forces Adsorbent layer

Amino acids

Factors affecting the mobility of Amino acids There are 2 main things which affect the rate at which a component will separate In chromatography: 1 – POLARITY OF AN AMINO ACID LIKE FOR LIKE A POLAR amino acid will interact more strongly (ADSORB) with the polar stationary phase (silica). If this is the case, the polar amino acid will not move up the plate that much A NON-POLAR amino acid will not interact strongly with the polar stationary phase and will be pushed up the plate. This is because the polar silica plate will prefer to interact with the polar mobile phase which will DISPLACE a non-polar amino acid.

Factors affecting the mobility of amino acids 2 – SIZE OF THE AMINO ACID The LARGER the amino acid, the SLOWER it moves up the plate. Which amino acid was the largest?

What about our amino acids? What can we say about the polarity of our amino acids? Unknown – Lysine – Leucine - Valine

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