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
200ml of water was then added to the filtrate in a 500ml beaker with constant stirring. White solid was formed in the process of addition and the solution was then left undisturbed in an ice bath for 10minutes. Once most of the solids had settled at the base of the beaker, the solution was decanted. 10ml of ethanol was added to the remaining suspension and was transferred in a clean centrifuge and centrifuged for 2minutes at 6000rpm. After the first centrifugation, the supernatant was discarded and the residue was washed by adding 14ml of ethanol.
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.
If the solute was wholly dissolved in the solvent before heating, it was recorded as a bad solvent. If the solute dissolved after being warmed in a water bath, it was set aside to cool to allow recrystallization; if their recrystallization occurred or not was recorded. If the crystals did not form previous to heating, the solution was placed in ice bath. After the ice bath, if the recrystallization did not occur then it was seeded. After completion of the solubility tests, the appropriate solvent, cyclohexane, was selected for large-scale recrystallization.
The sample was placed into appropriate vials as the liquid (L), and the vial was closed by the stopper. For 59.0℃ (acetone-rich side of azeotrope). 25 mL of chloroform and 75 mL acetone were added into the 250 mL round bottom flask. Small amount of boiling stone was added into the flask. The mixture was then distilled.
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 purified caffeine was scraped from the filter papers and its weigh was measured. The melting point of purified caffeine was estimated. Observations After mixing tea substance with methylene two clearly seen layers were obtained. During rotation of separatory flask the pressure was created inside and after the release of the pressure through the stem a little bump was observed. After the 5 minutes the methanol was rich with caffeine and its previously translucent white color changed to bright green.
Metal chelating activity Briefly, 2 mM FeCl2 was added to different concentrations of test sample and reaction was initiated by the addition of 5 mM ferrozine. The mixture was vigorously shaken and left to stand at room temperature for 10 min. Absorbance was measured at 562 nm after 10 min.8 % Inhibition = [(AB - AA)/AB] x 100, where AB, absorption of blank sample, AA, absorption of test sample. 2.6. Antibacterial
The residual biomass was separated by filtration and washed with distilled water. For alginate extraction, the acidified algal biomass was suspended in 3% Na2CO3 solution at different alkali: alga ratio (20, 40, and 60 mL/g). The different extraction temperatures ranged from 25 to 45º C, and lasted for 1 to 3 h. For each experimental run, sodium alginate was collected by filtration and precipitated with absolute ethanol (1:2 v/v). The mixture was maintained at 4º C overnight. The precipitate was collected by vacuum filtration and allowed to dry at room temperature.