The Rf values are 0.70 for salicylic acid and diflunisal,
0.67
for aspirin and methyl salicylate
Why does aspirin have a high Rf value?
In general, the adsorptivity of compounds increases with increased polarity (i.e. the more polar the compound then the stronger it binds to the adsorbent).
Non-polar compounds move up the plate most rapidly
(higher Rf value), whereas polar substances travel up the TLC plate slowly or not at all (lower Rf value).
What is the Rf value for ibuprofen?
Rf values were found to be
0.40, 0.94, 0.66, 0.27, 0.83
for ibuprofen, 4-isobutylacetophenone, famotidine, famotidine acid and basic degradation products, respectively. The second method is by HPLC on C18 column using methanol: phosphate buffer pH 3 (80:20, v/v) as a mobile phase.
What is the Rf value of caffeine?
While the Rf value from the analysis of pure caffeine is
0.70
; 0.71; 0.72.
What is the Rf value for paracetamol?
The solvent system was found to give compact spot for chlorzoxazone (Rf values of 0.23 ± 0.021), diclofenac sodium (Rf values of 0.51 ± 0.035) and paracetamol
(Rf values of 0.64 ± 0.028)
.
How do you explain Rf values?
In thin-layer chromatography, the retention factor (Rf) is used to compare and help identify compounds. The Rf value of a compound is
equal to the distance traveled by the compound divided by the distance traveled by the solvent front
(both measured from the origin).
What is the Rf factor and how is it calculated?
The Rf value is the retention factor used in the identification of organic compounds in a mixture. The Rf value is calculated by
measuring the relative distance traveled by a particular organic compound with respect to the mobile phase
. It is calculated in both paper chromatography and TLC.
What does a high Rf value mean?
What does a high RF value indicate? A high Rf (Ie 0.92) would refer to a
substance that is very non-polar
. Ie that substance moved a 92% of the entire distance the solvent traveled. … IE that substance was only able to move 10% of the entire distance the solvent traveled.
How do you reduce Rf values?
If you want the Rf of your TLC spot to be smaller, i.e., the spot to be lower down on the plate, you must
decrease the eluent polarity
. Either choose a different eluent (solvent) or adjust the solvent ratio by increasing the percentage of the nonpolar solvent relative to the polar solvent in the eluent.
Is a higher Rf value better?
Non-polar compounds move up the plate most rapidly
(higher Rf value), whereas polar substances travel up the TLC plate slowly or not at all (lower Rf value).
What drug is in caffeine?
Caffeine is
a stimulant drug
, which means it speeds up the messages travelling between the brain and the body. It's found in the seeds, nuts and leaves of a number of different plants, including: Coffea Arabica (used for coffee) Thea sinensis (used for tea)
How do you increase Rf value?
Rf values increase with
increasing solvent polarity
as substance are more attracted to the solvent and therefore move with it.
Can two compounds have the same Rf value?
The larger an Rf of a compound, the larger the distance it travels on the TLC plate. … If two substances have the same Rf value,
they are likely (but not necessarily) the same compound
. If they have different Rf values, they are definitely different compounds.
Is paracetamol a pain killer?
About paracetamol for adults
Paracetamol is
a common painkiller used to treat aches and pain
. It can also be used to reduce a high temperature. It's available combined with other painkillers and anti-sickness medicines. It's also an ingredient in a wide range of cold and flu remedies.
How is paracetamol synthesized?
Synthesis of Paracetamol (Morning)
Paracetamol is made by
reacting 4-aminophenol with ethanoic anhydride (more commonly called acetic anhydride)
. This reaction forms an amide bond and ethanoic acid as a by- product. When the reaction is complete the paracetamol is then isolated and purified.
Which is the Colour of paracetamol sample?
The color of this reagent (NQS) changed to
red
immediately before the injection of paracetamol to the system. However, this color was found to be unstable when allowed to stand. This is due to the stability of the reagent (NQS) in the basic medium upon standing.
