This topic contains a solution. Click here to go to the answer
« previous next »

Author Question: A mixture of compounds is spotted on a TLC plate and developed in 90:10 hexane:ethyl acetate. ... (Read 67 times)

renzo156

  • Hero Member
  • *****
  • Posts: 526
on: Aug 23, 2018
A mixture of compounds is spotted on a TLC plate and developed in 90:10 hexane:ethyl acetate. Visualization with both UV and iodine shows a single spot at the origin. What mixture of hexane and ethyl acetate should you try next? Explain.

Question 2

Why is it a problem to have the spotting line on a TLC plate below the solvent level in the developing chamber?


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

Brenm

  • Sr. Member
  • ****
  • Posts: 359
Reply #1 on: Aug 23, 2018
Answer to Question 1

You should increase the polarity of the solvent system by increasing the concentration of ethyl acetate, for example, to 90:10 ethyl acetate:hexane. The compounds are all polar and are adsorbed strongly onto the polar stationary phase. A significantly more polar mobile phase should be used to move the compounds with the mobile phase. A more polar solvent with more similar intermolecular forces will help dissolve the compounds into the mobile phase. In addition, the more polar solvent will help displace the compounds from the stationary phase because there are more mobile phase molecules than there are molecules of the compounds being analyzed.

Answer to Question 2

If the spotting line is below the level of the solvent in the developing chamber, significant amounts of the spotted material will dissolve in the solvent and be removed from the TLC plate.


renzo156

  • Member
  • Posts: 526
Reply 2 on: Aug 23, 2018
Excellent

Missbam101

  • Member
  • Posts: 341
Reply 3 on: Yesterday
:D TYSM

« previous next »
 

Did you know?

Cytomegalovirus affects nearly the same amount of newborns every year as Down syndrome.

Did you know?

In ancient Rome, many of the richer people in the population had lead-induced gout. The reason for this is unclear. Lead poisoning has also been linked to madness.

Did you know?

The term bacteria was devised in the 19th century by German biologist Ferdinand Cohn. He based it on the Greek word "bakterion" meaning a small rod or staff. Cohn is considered to be the father of modern bacteriology.

Did you know?

Oxytocin is recommended only for pregnancies that have a medical reason for inducing labor (such as eclampsia) and is not recommended for elective procedures or for making the birthing process more convenient.

Did you know?

People who have myopia, or nearsightedness, are not able to see objects at a distance but only up close. It occurs when the cornea is either curved too steeply, the eye is too long, or both. This condition is progressive and worsens with time. More than 100 million people in the United States are nearsighted, but only 20% of those are born with the condition. Diet, eye exercise, drug therapy, and corrective lenses can all help manage nearsightedness.

Spotted hyena with a wildebeest skeleton in Karatu, Arusha, Tanzania Spotted hyena with a wildebeest skeleton in Karatu, Arusha, Tanzania
In 1839 Mary Cragin, at the age of twenty-nine, became a convert to John Humphrey Noyes’s “communism In 1839 Mary Cragin, at the age of twenty-nine, became a convert to John Humphrey Noyes’s “communism
Hydrolysis reactions for some biochemically important phosphate compounds (part 3) Hydrolysis reactions for some biochemically important phosphate compounds (part 3)
The per capita emissions of the developed world The per capita emissions of the developed world
A variety of organic compounds from food can enter the reactions of aerobic respiration. A variety of organic compounds from food can enter the reactions of aerobic respiration.
Video: Diversity of Living Creatures - Charles Darwin & the Beagle's Voyage

For a complete list of videos, visit our video library