Decomposition of Aspirin Studied with UV/Visible Absorption Spectroscopy Aims: To determine the concentration of salicylic acid, formed from the hydrolysis of Aspirin, at regular intervals using the UV/Visible Absorption Spectroscopy From the concentration of salicylic acid, concentration of Aspirin to be determined using an equation Calculate the rate constant of this reaction and its order from a plot of graph of ln(aspirin) vs time Discuss the overall flaws and improvements to the experiment Results: As per schedule1, 0.212g of aspirin was added to 50 ml boiling water to form salicylic acid in a 100 ml flask, of which 1 ml was then pipetted to a 50 ml volumetric flask at the 5th min. Following an ice bath, the solution was mixed
The sample was transferred to a 250 ml conical flask kept in water bath for alkali treatment. 75 ml of 17.5% caustic soda was measured using a measuring cylinder at 20°C. 15 ml of 17.5% NaOH was added and fibres were macerated gently with a flattened glass rod for 1 minute. 10 ml more NaOH was added and the solution was mixed for 45 seconds. 10 ml NaOH was again added and mixed for 15 seconds to make lump free slurry.
The resultant spectrum is usually a graph of intensity of emitted or absorbed radiation versus wavelength or frequency. The spectra used in spectroscopy varies from ultra-violet, visible, infra red ranges. The wavelength range for the three spectra are 0-400, 400-700 and above. In short, spectroscopy use to gain insight into the structure of molecules or the concentration of atoms or molecules in a sample. The chemists use infrared radiation to determine the structure of a new molecule, geologists uses ultraviolet radiation to determine the concentration of particular element in rock or
The buret is filled to a point above the "0" mL mark with NaOH solution. In order to fill the tip of the buret with liquid, the solution is drained out of the bottom until the meniscus lies between the "0" and "1" mL marks. The initial buret reading can now be recorded to the nearest 0.01 mL. If you have any doubts as to your ability to read the buret correctly, ask your instructor to check your initial reading. Standardization of NaOH solution Accurately weigh out a sample of approximately 0.3-0.4 g of primary standard potassium hydrogen phthalate, KHPh, which has been previously dried at 120°C.
Twenty tablets were weighed accurately and powdered. An amount of the powder equivalent to 5 mg of amoxicillin trihydrate (content of one tablet) was dissolved in 60 ml of diluent. The solution was stirred for 10 min using a magnetic stirrer and filtered into a 100 ml volumetric flask through 0.45µ nylon membrane filter. The residue was washed 3 times with 10 ml of diluent and then the volume was completed to 100 ml with the same solvent. This solution was diluted with diluents to gae a concentration of 0.1 mg/ml solution each of Amoxicillin trihydrate.
Eventually using the NaOH and the acid’s consumed moles, the equivalent mass will be determined. Procedure: Part 2: Obtain 45mL of NaOH, and then weigh 0.3-0.4g of the unknown acid (KH2PO4). Dissolve the acid into 20.00mL water.
Before adding the iodine solution, the initial reading of the burette was taken. Then, the titration was started using the iodine solution into the burette with continuous swirling of the flask slowly and carefully. Once the color change started to appear, titration was stopped and final burette reading was recorded. Finally, the amount of vitamin C in the mandarin orange was calculated by using the standardization factor and used iodine solution.
Detection and Purification A Monascus pigments is a complex of azaphilone compounds, which can be separated by using various analytical techniques. UV- Visible spectrophotometric methods The UV-Visible spectrophotometric method is usually used for the confirmation of pigments produced by Monascus with taking absorbance at a respective wavelength. i.e. Yellow pigment at 400, Orange 470, and Red at 500 nm.
• Phenolphthalein indicator solution. • Standard aqueous potassium hydroxide or sodium hydroxide solution 0.1N or 0.5N. The solution should be stored in a brown glass bottle and colorless. Procedure: 1. Mix the mustard oil thoroughly before weighing.
Then, it was heated continuously at least 2 hours till a clear colorless solution was obtained. After finishing the heating process, the tubes which contained the mixture were left to cool and removed from the digestion unit. 50ml of distilled water was added to the digestion tube and 70ml of NaOH was added by the NAOH pump of the system. When the distillation was done, 50ml boric acid (4%) was added into the 250 ml flask. Steam distillation was applied and boric acid & ammonia were obtained.
50 μL of these dilution solutions were separated on the TLC plate coated with SNISG. The plate was developed with petroleum ether: ethyl acetate (4:1) and the movement of solvent was usually controlled at 1 cm from the upper edge. After completion, the plate was dried until no solvent smell remained. It was sprayed with an ethanol solution containing 10% sulfuric acid, and heated at an infra-red drier until obvious color came up, as shown in Fig.2 (B.ab). Simultaneously, the amount of silver nitrate in the impact of isolative effect was investigated with the sample procedure, as shown in Fig.2
Add another 25cm3 of Methanol and Ethyl acetate to the solutions. Stir gently for 20 minutes using a stirring rod this is to allow more of the active ingredients to mix with the solution. 16. Take two funnels and place one in two separate clean measuring beakers making sure the bottoms of the funnels don’t touch the bottom of the measuring beakers. Take two pieces of filter paper and press one onto each funnel.
Examine the C Elegans to insure that the C Elegans have survived at the room temperature and continue to have multiple C Elegans surviving. Once this is done prepare the dilutions of all the subjects which we are testing. Start with 1% solution for Nitrate-N 100ml and move 10ml of the first well into the next. Fill the well with 90ml dh20 to reach 100ml. move 10ml of the second well to the third well.
After measuring the amount of water needed (50 mL), put the beaker of water back into the freezer to maintain its temperature. Pour 50 mL of cold water into one detached chamber. Place the chamber with water and the chamber without water on a table side by side.
Before starting the heating process, measure the weight of the crucible with its cover first and then tare the balance, and after that adding about 1 gram of the sample to the crucible with its cover, and then weigh it. Moreover, it is possible liberating harmful gases during the process of heating; therefore, being careful is important. The heating process ends when this sample changes the color to brown because water of hydration is removed to the sample. Additionally, give time to the small cool down and measure its weight. Next, transfer the sample to a 50 mL beaker and mixes with distilled water, which gets by rinsing the crucible with its cover in 8mL, so the solution is generated.