Lab 5: isolation of B-Carotene form Spinach Leaves Flashcards
What is the function of B-carotene in plants?
it is a pigment that is involved in photosynthesis
What class of compounds is B-carotene in? Is it polar?
carotenoids
nonpolar
What is the color of B-carotene?
yellow
What class of compounds are the oxygen-containing derivatives of carotenes?
xanthophylls
What is the reason why a layer of sand is placed on top of the adsorbent in column chromatography?
The sand protects the adsorbent from being disturbed as mobile phase is added
What are the correct units of absorbance in US spectroscopy?
trick question. No limits
What is the name of the law that relates the absorbance of a compound to its concentration?
Beer-Lambert Law
Why is TLC typically performed before column chromatography?
to determine the solvent system to use
What is the procedure that will help saturate a TLC developing chamber with developing solvent vapors?
- place a paper wick inside the chamber
- cover the chamber
- gently swirl the solvent in the chamber before putting the TLC plate inside
Two samples are spotted onto a TLC plate, and the plate is developed and visualized. The result is Sample A separated into three visible spots and Sample B only gives one visible spot. Why is this?
Sample b contain at least one compound
What is the substance that is typically used as an adsorbent in column chromatography?
silica gel
What is the reason why the adsorbent in column chromatography should never be allowed to dry/
crack form due to air pockets in the adsorbent and this will negatively impact the separation
What is the approximate amount of adsorbent that should be used in a column chromatography separation?
the mass of adsorbent should be 20-50 times the mass of the sample
