A total of 0.1 ml of supernatant was added to cuvette containing 1.9 ml of 50mM phosphate buffer (pH 7). The reaction was started by the addition of 1 ml freshly prepared 30mM H2O2. The rate of decomposition of H2O2 was measured spectrophotometrically at 240 nm. Catalase values were expressed as n moles H2O2 consumed/min/mg protein. Measurement of lipid peroxidation TBARS, a measure of lipid per oxidation, was measured as described by Ohkawa .
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.
Linoleic acid peroxidation was initiated by the addition of 4 mM FeSO4.7H2O, incubated for 60 min at 37oC and terminated by the addition of 2 mL of ice cold trichloroacetic acid (10% v/v). An amount of 1 mL of thiobarbituric acid (1% w/v in 50 mM NaOH) was added to 1 mL of the reaction mixture, followed by heating at 95oC for 60 min. The reaction sample was read at 532 nm.7 The percentage of linoleic acid peroxidation inhibition activity was calculated using the following equation: % Inhibition = [(AB - AA)/AB] x 100, where AB, absorption of blank sample, AA, absorption of test sample. 2.5.4. 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.
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. After the preceding treatments, solutions were filtered and injected into the HPLC
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
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.
Fe3O4 nanoparticles were synthesized according to our previously reported method by chemical co-precipitation of Fe2+ and Fe3+ ions with a molar ratio of 1:2 . Briefly, 2.4 g of FeCl3.6H2O and 0.8 g of FeCl2.4H2O were dissolved in 30 mL of deionized water under using continuous N2 purge at 70 °C. and Under vigorous stirring, followed by dropwise addition of 10 mL of NH3.H2O was dropwise added to the reaction mixture until the color of mixture turned to black and kept reacting for 90 min to complete the reaction. At the end, the synthesized Fe3O4 nanoparticles were separated by a magnet and washed by using water and ethanol for further three times with 89.3%
H2SO4 • Catalyst: potassium sulphate (K2SO4), copper (II) sulphate pentahydrate (CuSO4.5H2O) • NaOH (40%) • 0.1 N HCl solution • Boric acid (4%) • Indicator: methyl red (200 mg make up to 100 ml with %95 ethanol ) 1 gram Feta Cheese was used as a sample in this experiment. First of all, the experiment was started with the digestion phase which was performed by mixing 10g potassium sulphate and 0.5 g CuSO4 solution that acts as catalyst, and added 20ml conc. H2SO4. The digestion unit temperature was set to 420±10°C and preheated for 15 minutes. Then, it was heated continuously at least 2 hours till a clear colorless solution was obtained.
To start an experiment of adsorption isotherm, Cu(II) aqueous solution of 100 ml with the predetermined varying initial concentration of Cu(II) in the range of 6.5-370.5 mg/l and the best activator composition of NaOH was put into the erlenmeyer flask and stirred using a magnetic stirrer at 75 rpm, room temperature of 298.15 K (± 2 K), 1 atm and normal pH. The experiment was stopped at 119 mins contact time for sampling. The samples of 1 ml were placed in a 20-ml vial and diluted with 10 ml distilled water, and filtered using a syringe filter. The filtrate was placed in 10-ml vial for the AAS analysis. To determine the concentration Cu(II) in the samples from the AAS reading, dilution factor was taken into
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.