Experiment 2: Column Chromatography Flashcards
(41 cards)
What will be done in this lab mainly?
We will isolate and separarte B-carotene and chlorophylls A and B from spinach leaves.
Define Natural Products
Molecules that are made by nature and are naturally occurring in our environment.
What is the compound made by poison ivy?
Urushiol
What is the toxin that can be made from pufferfish?
Tetrodotoxin
Are chlorophylls and B-carotene natural products?
Yes, they are.
What is the significance of chlorophyll?
They are responsible for the plant’s green color and its main role is to absorb light energy to turn water and carbon dioxide into chemical energy, a process called photosynthesis.
What is the benefit of chlorophyll for humans?
It acts as a source of magnesium that’s important for heart and muscle health.
What does the chemical structure of chlorophyll resemble?
Resembles the structure of hemoglobin, a molecule that is responsible for transporting oxygen in the blood.
What is the major difference between hemoglobin and chlorophyll?
The central metal atom: magnesium in chlorophyll and iron in hemoglobin.
What is the significance of the human body being able to swap magnesium for iron?
From that, you are able to turn chlorophylls into hemoglobin.
What are some significant things to note about B-Carotene?
It is the compound that gives carrots their orange color; additionally, it is an anti-aging molecule, fights oxidative stress and cognitive decline. It is also a precursor to vitamin A.
What can B-Carotene be found in?
Kale, Asparagus, Spinach, Mangoes, Melons
Define Chromatography
General term applied to several separation methods that utilize the physical properties of solutes in a mixture and the solvents used to separate them.
Define Thin Layer Chromatography
An analytical method used to determine whether a substance is pure or a mixture of compounds. Two phases are used for separation: the mobile and stationary phase.
Define Stationary Phase
Made of adsorbent (able to absorb other molecules) material that competes with the mobile phase for the attraction of individual solutes in a mixture.
What does “thin layer” refer to in thin layer chromatography?
The use of a thin plate of silica gel that acts as the stationary phase.
Define Mobile Phase
The mobile phase is consisted of a solvent or a combination of solvents that vary in polarity.
Describe the process that happens in TLC.
The molecules are attracted to both the stationary and the mobile phase and will partition between them as the solvent up the stationary phase by capillary action.
How is a chromatogram made?
Individual solutes travel different rates as they are carried by the solvent. So, the variable rates by which the components travel produce a pattern called a chromatogram.
How do extremely polar molecules move in TLC? How about non-polar/less polar substances?
Since the silica gel that makes up the stationary phase is polar, polar solutes that have a strong attraction for the stationary phase will move the shortest distance.
On the other hand, molecules that have the least affinity for the stationary phase will move the furthest.
Define Retention Factor
The distance the components of a mixture move on chromatography paper compared to the distance the solvent moves.
Where do the Rf values fall and what do they indicate? Also, what is the formula for Rf?
They fall between 0-1. A value of 0 indicates that the component did not move with the solvent (mobile phase) and a value of 1 indicates that the component mostly interacted with the mobile phase and was not retained by the stationary phase.
Rf= distance to center of spot/distance to solvent front
What is the relationship between polarity and Rf values?
They have an inverse relationship.
What is the most common technique for purifying mixtures of compound in O-chem?
Column chromatography
