Precautions
There are several factors that affect the Rf values of a particular analyte:
- Stationary phase
- Concentration of stationary phase
- Mobile phase
- Concentration of mobile phase
- Temperature
What is the Rf value for aspirin using TLC?
The Rf value represents the difference between the migration of the developing solvent and the compound being evaluated in Thin-Layer Chromatography (TLC). The Rf value serves as a simple measurement of the relative binding of the compound of interest under the experimental conditions.
What does Rf value mean in TLC?
To make sure this medicine is safe for you, tell your doctor if you have:
- asthma or seasonal allergies;
- stomach ulcers;
- liver disease;
- kidney disease;
- a bleeding or blood clotting disorder;
- gout; or
- heart disease, high blood pressure, or congestive heart failure.
What is aspirin best used for?
Ibuprofen
- 1 Structures
- 2 Names and Identifiers. ...
- 3 Chemical and Physical Properties. ...
- 4 Spectral Information. ...
- 6 Chemical Vendors
- 7 Drug and Medication Information
- 8 Pharmacology and Biochemistry. ...
- 9 Use and Manufacturing. ...
- 10 Identification. ...
- 11 Safety and Hazards. ...
What is the Rf value of ibuprofen?
What is the Rf value for acetaminophen?
The Rf values of the isolated acetaminophen, pure acetaminophen and Excedrin were all within 0.06. This is most likely due to the contamination of the TLC plate with Excedrin.
Why does salicylic acid have a higher Rf value than aspirin?
Due to higher interaction among molecules, salicylic acid is less attracted to the stationary phase and will move further up the plate thus having a higher Rf value than the standard salicylic acid and a closer Rf value to the acetylsalicylic acid in the reaction mixture.
What is the Rf value of caffeine?
The Rf value of caffeine standard was 0.63, and every sample showed similar value with caffeine standard, indicating that all samples contain caffeine.
What is more polar salicylic acid or aspirin?
The difference between the two is that aspirin is salicylic acid with the free OH of salicylic acid having been esterified. Both compounds still have the -COOH group. So, it comes down to comparing -OH to -OC=OCH3. The -OH group is more polar than the ester so salicylic acid is more polar than aspirin.
What is the Rf value of 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.
What solvent is used TLC for aspirin?
A range of solvents can be used for the recrystallisation of aspirin, but one of the best and cheapest is a 5 %(v/v) ethanol/water mixture. Prepare this solvent by combining water (95 mL) and ethanol (5 mL) in a 250 mL conical flask.
Is aspirin more polar than caffeine?
Acetaminophen has a phenol and amide function group, but caffeine has multiple amide functional groups; therefore, acetaminophen is more polar than aspirin and less polar than caffeine.
Is aspirin more polar than ibuprofen?
(Acetaminophen; Aspirin; Caffeine, and Ibuprofen) D cafteine > Acetaminophen > phenacetin > Aspirin> ibuprofen Aspirin is more polar than ibuprofen more H bond acceptors and donators acetamingghen phenacetin it has a OH that can H bond .
What is the Rf value?
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).
How does TLC determine purity of aspirin?
The purity of your aspirin samples will be tested using a technique called thin-layer chro- matography or TLC for short. Chromatography separates compounds in a mixture from one another based on their different polarities.
What intermolecular forces are present in aspirin?
Both salicylic acid and aspirin are polar organic compounds and, in their pure forms, the intermolecular forces present are , attractions and dispersion forces.
Is Ibuprofen polar or nonpolar?
Ibuprofen has a polar end, the carboxylic acid group, which can act both as a hydrogen donor and a hydrogen acceptor establishing moderate to strong interactions with other polar molecules.
What is the Rf value?
The Rf value is defined as the ratio of the distance moved by the solute (i.e. the dye or pigment under test) and the distance moved by the the solvent (known as the Solvent front) along the paper, where both distances are measured from the common Origin or Application Baseline, that is the point where the sample is
What is the RF value of caffeine?
Furthermore, what is the RF value of caffeine? While the Rf value from the analysis of pure caffeine is 0.70; 0.71; 0.72. The Rf values which indicate the results of the qualitative analysis of pure caffeine.
What is the Rf value of gentisic acid?
The Rf values are 0.70 for salicylic acid and diflunisal, 0.67 for aspirin and methyl salicylate, 0.60 for gentisic acid, 0.57 for p-aminosalicyclic acid, and 0.40 for salicyluric acid.
How much aspirin is lethal?
The lethal dose of aspirin for an adult is probably in the region of 25 to 30 g but recovery has been achieved by appropriate treatment after the ingestion of twice or thrice this amount.
How many aspirin tablets should be stored?
Chewable aspirin tablets containing 81 mg of the drug should be stored in child-resistant containers holding not more than 36 tablets each in order to limit the potential toxicity associated with accidental ingestion in children. Aspirin suppositories should be stored at 2-15 °C.
What is the most commonly used analgesic and antipyretic medication?
Aspirin or acetylsalicylic acid is perhaps the most commonly used analgesic and antipyretic medication worldwide, having been in clinical use for over 100 years.
How long does it take for aspirin to be detected in breast milk?
Acetylsalicylic acid and the acetylsalicylate ion were detected in the breast milk of nursing mothers within 1 hour of aspirin (acetylsalicylic acid) ingestion (1).
What is acetylsalicylic acid?
**Pain, fever, and inflammation** Acetylsalicylic acid (ASA), in the regular tablet form (immediate-release), is indicated to relieve pain, fever, and inflammation associated with many conditions, including the flu, the common cold, neck and back pain, dysmenorrhea, headache, tooth pain, sprains, fractures, myositis, neuralgia, synovitis, arthritis, bursitis, burns, and various injuries. It is also used for symptomatic pain relief after surgical and dental procedures [FDA label]. The _extra strength_ formulation of acetylsalicylic acid is also indicated for the management migraine pain with photophobia (sensitivity to light) and phonophobia (sensitivity to sound) [FDA label]. **Other indications** ASA is also indicated for various other purposes, due to its ability to inhibit platelet aggregation. These include: Reducing the risk of cardiovascular death in suspected cases of myocardial infarction (MI) [FDA label]. Reducing the risk of a first non-fatal myocardial infarction in patients, and for reducing the risk of morbidity and mortality in cases of unstable angina and in those who have had a prior myocardial infarction [FDA label]. For reducing the risk of transient ischemic attacks (TIA) and to prevent atherothrombotic cerebral infarction (in conjunction with other treatments) [FDA label]. For the prevention of thromboembolism after hip replacement surgery [FDA label]. For decreasing platelet to platelet adhesion following carotid endarterectomy, aiding in the prevention of transient ischemic attacks (TIA) [FDA label]. Used for patients undergoing hemodialysis with a silicone rubber arteriovenous cannula inserted to prevent thrombosis at the insertion site [FDA Label]. **Important note regarding use of the extended-release formulation [F4405]** In the setting of acute myocardial infarction, or before percutaneous interventions, the extended-release form of acetylsalicylic acid should not be used. Use immediate-release formulations in scenarios requiring rapid onset of action [Label, F4405]. The extended-release form is taken to decrease the incidence of mortality and myocardial infarction (MI) for individuals diagnosed with chronic coronary artery disease (CAD), including patients with previous myocardial infarction (MI) or unstable angina or with chronic stable angina. Additionally, the extended-release form is used to decrease the risk of death and recurrent episodes of stroke in patients with a history of stroke or TIA [F4405].
What is ASA in a blood test?
Acetylsalicylic acid (ASA) blocks prostaglandin synthesis. It is non-selective for COX-1 and COX-2 enzymes [A177241, A10989, A32682]. Inhibition of COX-1 results in the inhibition of platelet aggregation for about 7-10 days (average platelet lifespan). The acetyl group of acetylsalicylic acid binds with a serine residue of the cyclooxygenase-1 (COX-1) enzyme, leading to irreversible inhibition. This prevents the production of pain-causing prostaglandins. This process also stops the conversion of arachidonic acid to thromboxane A2 ( TXA2 ), which is a potent inducer of platelet aggregation [FDA label]. Platelet aggregation can result in clots and harmful venous and arterial thromboembolism, leading to conditions such as pulmonary embolism and stroke. It is important to note that there is 60% homology between the protein structures of COX-1 and COX-2. ASA binds to serine 516 residue on the active site of COX-2 in the same fashion as its binding to the serine 530 residue located on the active site of COX-1. The active site of COX-2 is, however, slightly larger than the active site of COX-1, so that arachidonic acid (which later becomes prostaglandins) manages to bypass the aspirin molecule inactivating COX-2 [A32682, A177256]. ASA, therefore, exerts more action on the COX-1 receptor rather than on the COX-2 receptor [A177268]. A higher dose of acetylsalicylic acid is required for COX-2 inhibition [A177325].
Is aspirin hydrolyzed?
Acetylsalicylic acid is hydrolyzed in the plasma to salicylic acid. Plasma concentrations of aspirin following after administration of the extended-release form are mostly undetectable 4-8 hours after ingestion of a single dose. Salicylic acid was measured at 24 hours following a single dose of extended-release acetylsalicylic acid [F4405]. Salicylate is mainly metabolized in the liver, although other tissues may also be involved in this process [FDA label]. The major metabolites of acetylsalicylic acid are salicylic acid, salicyluric acid, the ether or phenolic glucuronide and the ester or acyl glucuronide. A small portion is converted to gentisic acid and other hydroxybenzoic acids [FDA label].
How to find Rf of aspirin?
Rf values are found by chromatographic experiments. Aspirin is a polar molecule and will be more soluble in a polar solvent. As the general rule of solubility ‘like dissolves like’ suggests. The Rf values are always different for different stationary and mobile phases used. So, an aspirin solution is to be run against a polar solvent (mobile phase) when the stationary phase is less polar than the mobile one. This will leave aspirin at a specific height giving its Rf value between 0 and 1.
What is the Rf value of analytes?
So, the Rf values for the analytes (A) and (B) are 0.725 and 0.325.
Why is the relative affinity of analytes with stationary and mobile solvents different?
The more the relative affinity with a stationary phase an analyte has, the more it will stay in place and the lesser the Rf value will get and vice versa.
What is Rf in chemistry?
Rf = Distance moved by analyte (A) / Distance moved by solvent front
Why do same substances have different Rf values?
Same substances (analytes ) have different Rf values if the nature of stationary and mobile phases is changed , i.e. the affinity factors are changed. Similar is the case when the concentration of these phases is changed. Temperature affects the rate of mobile action of solvent and also the solubilities of analytes in the solvent.
What is Rf value?
Rf value is the characteristic identification value for analytes at given temperatures. It means that compounds can be analyzed and identified based on their Rf values. It is, however, not the case when a new compound is discovered.
Why is Rf not 0?
Rf values must not be either 0 or 1 because both of these conditions are not useful in the analytical procedure . An Rf value of zero means that the complete displacement (migration) of the analyte with the mobile phase (solvent), whereas the value one refers to no displacement at all.
