After the specified time, the solutions were completed to mark by using distilled water to achieve a final concentration of 20 µg/mL each, filtered and injected into the HPLC system. Dry Heat Degradation For thermal stress, 10 mg portions of each of VAL and SAC dry powder were placed in porcelain dish in a controlled-temperature oven at 100˚C for 4 hours. After the specified time, the content of the porcelain dish was transferred quantitatively with HPLC-grade methanol into a 10 mL volumetric flask and the volume was made to the mark by using the same solvent. Then, an aliquot of this methanolic stock was diluted to volume with distilled water to obtain a final concentration of 20 µg mL-1.
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.
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 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.
Briefly, a solution containing 0.3 gr (3 mmol) succinic anhydride and 0.4 ml (3 mmol) of triethylamine in 10 ml of THF was dropwise added to a stirred solution of 1 mmol of sPEG in 10 ml of anhydrous THF for 12 h at 75 C. The solvent of product solution was evaporated by a rotary evaporator and the obtained dark yellow viscous liquid was dissolved in acidic water (pH= 3). In the following,
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 subsequent centrifugation was repeated twice, only this time using 8ml of diethyl ether instead of ethanol.
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.
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.
One thermometer was then placed into the 20mL of water in each graduated cylinder and left to sit at room temperature. When both thermometers reached the same temperature (the assumed ‘room temperature’), the water from one graduated cylinder was transferred into a 100mL beaker. The water from the other graduated cylinder was poured into a polystyrene cup. Using a scale and a weighboat, precisely 2 grams of ammonium chloride (NH4Cl) was measured and placed into the polystyrene cup with the 20mL of water. The chemical compound and the water were mixed together using a glass rod until the chemical was thoroughly dissolved.
Add 50 to 100 ml of freshly neutralized hot ethyl alcohol and about one ml of phenolphthalein indicator solution. 4. Boil the mixture for about five minutes and titrate it against the standard alkali solution while shaking vigorously during the
The silver ion TLC was prepared through the following procedure: Silver nitrate was dissolved in 10 ml of distilled water. This aqueous solution of silver nitrate was absolutely mixed with 9 g of silica gel (10 ~ 40 μm particles). Then, a 10 × 5 cm TLC plate was coated with the above slurry and activated for 1 h at 90 °C before use. They were immediately transferred into a desiccator in dark for storage after cooling. 32 100 μL of afore-prepared sample solution and the mixed reference standard were diluted 100 times with ethyl acetate.
Then, the pipet was rinsed with distilled water. The bulbs were then attached to the pipette; filling and dispensing water were practiced using both bulbs. Furthermore, the 250-mL beaker was weighed, and its mass was recorded. After that, the Erlenmeyer flask was filled with 100 mL of distilled water. The temperature was recorded.
Experimental Clay-catalyzed dehydration of cyclohexanol Cyclohexanol (10.0336 g, mmol) was added to a 50 mL round bottom flask containing five boiling chips, Montmorillonite K10 clay (1.0430 g) was then added to the cyclohexanol and the mixture was swirled together. The flask was then placed in a sand bath and attached to a simple distillation apparatus. The contents of the flask were then heated at approximately 150 °C to begin refluxing the cyclohexanol. The distillation flask was then loosely covered with aluminum foil and the hood sash was lowered in order to minimize airflow. As the reaction continued, the temperature was adjusted in order to maintain a consistent rate of distillation.
The purpose of this experiment was to learn about metal hydride reduction reactions. Therefore, the sodium borohydride reduction of the ketone, 9-fluorenone was performed to yield the secondary alcohol, 9-fluorenol. Reduction of an organic molecule usually corresponds to decreasing its oxygen content or increasing its hydrogen content. In order to achieve such a chemical change, sodium borohydride (NaBH4) is used as a reducing agent. There are other metal hydrides used in the reduction of carbonyl groups such as lithium aluminum hydride (LiAlH4).
The objective of this experiment was to create synthesize methyl eugenol from eugenol, dimethyl carbonate, and tetrabutylammonium bromide. To start off the experiment, a heating under reflux apparatus was used and the parts included: a water jacketed condenser, ring stand, tubes, flowing water, 25-mL round bottom flask, heating block, and a hot plate. There were two parts to the water condenser, entry and exit ways for water. The bottom opening was connected to the sink through one tube and the top opening was connected with a loose end, which was needed to get rid of the flowing water. To create the solution needed to synthesize methyl eugenol, approximately 0.200 g of eugenol (note: the measured g was converted to mg for later calculations) was measured, alongside approximately 1.2 g of TBAB and was added to the 25-mL round bottom flask.