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 supernatant was assayed for SOD activity by following the inhibition of epinephrine auto-oxidation. 0.5ml of sample was diluted with 0.5 ml of distilled water, to this 0.25 ml ethanol, 0.5 ml of chloroform (all reagents chilled) was added. The mixture was shaken for 1 min and centrifuged at 2000 rpm for 20 min. The enzymatic activity in supernatant was determined. To 0.05 ml of carbonate buffer (0.05 M, pH 10.2) and 0.5 ml of EDTA (0.49 M) was added.
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.
As it was done in the Experiment A, 20 drops of 0.2 M acetic acid and 10 drops of 2% starch solution was mixed well with the juice solution. 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.
Diazotized Sulphanilic Acid 1. Dissolve 1.1 g of anhydrous sodium carbonate in 50 mL of water in a 100 mL conical flask. 2. Add 4 g of sulphanilic acid to the solution and heat it until it dissolves. A small amount of suspended material may render the solution cloudy.
Another 5-mL test tube, labelled as B, was filled with 1 mL of distilled water. A drop of methyl red was added. Also, a 0.01M hydrochloric acid (HCl) was added in a dropwise manner from a syringe until the color of the solution matches that of the first test tube setup. The volume of the HCl used was recorded for the determination of the ionization constant of
5 mL of 3M sodium hydroxide, 5 mL of de-ionized water, and 15 mL of hexane were added to the reaction flask and stirred. The mixture was transferred to a separatory funnel, separated into an organic layer and water layer, and then drained. The water layer was washed twice with 10 mL of hexane. The organic layer was dried
The volumetric flask was then filled up to its 100 mL mark with deionized water. The buret was washed out with dionized water and then with the strong base NaOH before being filled up with NaOH. About 20 mL of the unknown weak acid was pipetted into a beaker. The starting volume of the NaOH in the buret was recorded before about 4 mL of the strong base was titrated into the weak acid solution. The final volume was recorded.
Hepcidin solution (20 μL) was added to the plasma before extraction with the beads, whilst in parallel another sample of plasma underwent extraction and then the same amount of hepcidin was added. The percentage of recovery was calculated as (AreaPRE / AreaPOST) x 100, where AreaPRE represents the samples with hepcidin added before bead treatment and AreaPOST the samples with hepcidin added after bead treatment. The values obtained were above 90 % in all cases. 4.4. Dietary intervention The functional juice aronia-citrus juice (ACJ) included in this study was a mixture of citrus juice (95%) and 5% aronia extract (Aronia melanocarpa), based on a drink model developed before and reported by Gonzalez-Molina et al .
2.2.1 Preparation of sPEG from polyoxyethylene (20) sorbitanmonolaurate (tween-20) Star shaped polyoxyethylene (sPEG) was synthesized according to the literature with some changes . Briefly, 8 g of polyoxyethylene (20) sorbitan monostearatev were dissolved in 20 ml of THF in a round bottom flask and then 1 g of KOH was added as hydrolysis agent. After refluxing about 24 h, the solution was concentrated and added to a mixture of acidic water/hexane (1 : 1). The aqueous phase in which the sPEG is dissolved was separated by a separation funnel from hexane. Next, the aqueous phase was neutralized with HCl and extracted with dichloromethane.