TLC Analysis of Analgesics Due to the versatility and inexpensiveness of thin layer chromatography, it is one of the most widely used techniques in laboratories today. Thin layer chromatography has many uses in the realms of pharmaceuticals, forensics, industry and most especially organic chemistry. More specifically, the main applications of TLC are to detect the presence of a particular compound in urine or blood, the ingredients and/or chemical composition of anything ranging from food to drugs, and plants to explosives. The way chemical compositions are analyzed via TLC by establishing the number of compounds or elements that exist in a reaction, whether or not the compounds are different and to check the progress of the reaction, which is determined based on the …show more content…
The components of an analgesic will be determined by noting the separation between the solid and liquid (or mobile) phases and comparing it to these predicted reference values. Some samples may contain more than one of these analgesic compounds and therefore have dots corresponding at multiple Rf values. However it is not only the chemical components that influence the Rf value. The eluting solvent mixture also has an effect. For instance, changing the solvent mixture can alter the Rf value and separation between the mobile/liquid phase and solid phases. For instance, the greater the polarity of the eluting solvent (ie methanol) the more polar the analyze, the slower it will move up the plate since the polar solvents will dissolve the polar analytics more effectively and move the analyses up the TCL plate at a faster rate. The more polar the solvent, the quicker the analyst will move. This means that we will get little separation on the plates. The opposite can be predicted for non-polar solvents such as
The spots moved 3.8cm, 2.3cm, 2.1cm, 1.8cm, and 2.5 cm, for the methyl benzoate, crude product, mother liquor, recrystallized product, and isomeric mixture, respectively. The Rf values were determined to be.475,.2875,.2625,.225, and.3125, for the methyl benzoate, crude product, mother liquor, recrystallized product, and isomeric mixture, respectively. Electron releasing groups (ERG) activate electrophilic substitution, and make the ortho and para positions negative, and are called ortho para directors. In these reactions, the ortho and para products will be created in a much greater abundance. Electron Withdrawing groups (EWG) make the ortho and para positions positive.
5. Two or more samples may be applied to each plate if they are kept
A TLC plate is used to see if all the benzyl in the solution has reacted to form
The aspirin crystals were packed into 3 small capillary tubes to ensure that they are compressed so as to prevent any air gaps. Subsequently, the aspirin crystals that are in the 3 capillary tubes are placed into the melting apparatus and the temperature range was recorded. Since the range is quite far from the theoretical value of 140°C, aspirin's purity attained was low due to impurities present. One potential reason is because of the swift cooling. When the aspirin is left to cool, the crystal lattices will form too rapidly which will surround other molecules thus making the aspirin impure. Another reason could be because the recrystallized aspirin has not dry completely and there might me left over solvent that will affect the temperature range of the aspirin.
Solution 3 had the lowest Rf value because of the polarity of the solutions. Aspartic acid is a charged amino acid, therefore it would have a stronger polarity, resulting in a lower Rf value. Phenylalanine is a hydrophobic amino acid, which is why we observed a relatively high Rf value. A solution of aspartame and hydrolyzed aspartame had relatively high Rf values. Since about 50% of aspartame is made of phenylalanine , the polarity of aspartame is lightly more nonpolar than polar. In plate II, Solution 7 had the lowest Rf value compared to the other solutions, which means it was the most polar
Marion Good, PhD, RN, has focused her study, “A Middle-Range Theory of Acute pain Management: Use in Research,” on complementary medicine for pain and stress, acute pain, and stress immunity. The purpose of this theory is to put into practice guidelines for pain management. Good, 1998, noted the need for a balance between medication usage and side effects of pain medications. The theory also promoted patient education related to pain management following surgery and encouraged plan development for acceptable levels of pain management. This theory was developed through deductive reasoning. Chinn & Kramer, 2008, defined deductive reasoning as going from a general concept to a more specific concept. Good, 1998, related that there was a balance between analgesia and side effects in which two outcomes can be deduced: (1) a decrease in pain, and (2) a decrease in side effects. These outcomes can be studied further or more detailed concepts can be deduced from them.
The conical vial was placed in a small beaker and allowed to cool to room temperature. The mixture was Cooled thoroughly in an ice bath for 15-20 minutes and crystals collected by vacuum filtration on a Hirsch funnel. The vial was rinsed with about 5 mL of ice water and transferred into to the Hirsch funnel and again washed with two additional 5mL portions of ice water. Crystals were dried for 5-10 minutes by allowing air to be drawn through them while they remained on the Hirsch funnel. The product was transferred to a watch glass plate and allow the crystals to dry in air. Crude acetaminophen product was weighed and set aside a small sample for a melting point determination and a color comparison after the next step. Calculation of the percentage yield of crude acetaminophen (MW = 151.2). was done and recorded in the lab notebook.
As explained by Saferstein “Chromatography is a means of separating and tentatively identifying the components of a mixtur... ... middle of paper ... ... ively place the suspect or perpetrator behind bars. Analyzing soil compounds can be measured by the levels of organic molecules including n-alkanes, fatty alcohols and fatty acids, which are all found in the waxy outer layer of plant matter (Geddes, 2008). It basically states that compounds can remain in the soil for thousands of years, which explains that each area being tested has its unique organic profile.
The term chromatography refers to different methods of molecular separation between a mobile phase and a stationary phase based on various physio-chemical properties. There are many types of chromatography that are used as analytical tools in environmental science, forensics, metallurgy, biology, etc. Some common examples are thin layer chromatography (TLC), gas chromatography (GC), high performance liquid chromatography (HPLC) and ion chromatography. Ion chromatography (IC) was introduced as an analytical technique by Small, Stevens, and Bauman in 1975. According to IUPAC in IC “separation is based on differences in the ion exchange affinities of the individual analytes. If inorganic ions are separated and can be detected by conductivity detectors or by indirect UV detection then this is also called ion chromatography” (Eith 17).
If the solid dissolved in the solvent at room temperature, then it was too soluble and that solvent could be eliminated. The acetanilide is completely dissolved in ethanol and dichloromethane, therefore eliminating them from being the suitable solvent. If the solid did not dissolve at room temperature then it was placed in the sand bath and left to boil. If the solid dissolved, it was placed in the ice bath and if crystals were observed coming out of the solution then the suitable solvent was found. The suitable solvent was water as the crystals came out once placed in the ice bath.
Analysis of Aspirin Tablets Aim --- To discover the percentage of acetylsalicylic acid in a sample of aspirin tablets. ----------------------------------------------------------------- In order to do this, the amount of moles that react with the sodium hydroxide must be known. This is achieved by using the method of back titration.
The choice of mobile phase depends on the chemical nature of the compound of interest and could be purely organic, inorganic or a mixture of both in gradient. Most commonly used mobile phases are organic solvents like acetonitrile or methanol. Some HPLC analysis require the use of water free solvents as mobile phase and in such cases acids like formic acid, phosphoric acid, trifluoroacetic or salts which will assist in separation of components in the sample are used.
... point, the complete and full separation of the components, as those seen in the first part of the experiment, did not happen. This source of determinate error decreased the Rf values. Furthermore, upon placing my TLC plate into the solution I stumbled and threw the TLC plate in the jar. The solution splashed up on the TLC plate, rushing solution to move up and absorb on the TLC plate without capillary action. Because not all the solution that splashed up was not absorbed, it may have either dragged down some of the ink components or allowed for faster capillary action. This source of indeterminate error skewed the result of the Rf values, either increasing or decreasing the distance traveled of the ink. I don’t believe that this was a great source of error because the components of the unknown ink and the pen #3 still rose to similar values with similar separation.
Chemical sensors contain two main components; the recognition element, which is the part of the sensor that imparts selectivity so the sensor can select a specific analyte and avoid any interferences, and the transducer. Transducers are the detector part of the sensor, it responds to the change in chemical or physical property of the sensor and translates the magnitude of the signal into a readable measure of the amount of the analyte.3
The recommended Linearity Range to be covered is 80% – 120%, in practice however, the covered range is usually 50% - 150%, this is needed to include the worst case scenario and other evaluation of the behaviour of tablets and capsules during the in process controls for example (e.g., dissolution testing, where at certain point of the dissolution the full release is not achieved yet and only say 60% is in the media, therefore to create reliable dissolution profile the assay methods that covers the lower ranges are favoured)