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
The duration was set to 180 seconds, and the rate was at 15 seconds/sample. Part B of the experiment was performed in a coffee cup calorimeter that was cleaned between each reaction. 50mL of 2MHCl was measured using a graduated cylinder that got poured into the cylinder in one swift motion. The probe was inserted through the lid, and was made sure that it wasn’t touching the bottom of the cups. LabQuest was run for 3-4 readings, before the NaOH was poured in one motion into the calorimeter, with a stir bar mixing the solutions.
20ml of it was then pipetted into a 250 Erlenmeyer flask, followed by setting up a titration system with 0.100M HCl in the burette. As in the case of titration of an acetic acid with sodium hydroxide, a pH meter was used to monitor the pH of the solution as HCl was being added. HCl was added in an interval of 1ml until the pH of the solution was 9. When the solution pH reached 9.5, HCl was added in an increment of 0.2ml until the equivalence was passed. After this, HCl was added in an interval of 1ml until there was minimal change in the solution pH.
A flame test and a halide ion test were performed. To start with the flame test, weigh 1 gram of Unknown substance in an analytical balance using a scoopula and mixed it in with 20 mL of water into a 150 mL. Repeat the same step with NaC2H3O2. Repeat the same step for the flame test and record down data. Lastly is the halide ion test.
This was filtered and the extract was concentrated on a water bath to one quarter of the original volume. Concentrated ammonium hydroxide was added drop wise to the extract until the precipitation was complete. The whole solution was allowed to settle and the precipitate was collected and washed with dilute ammonium hydroxide and then filtered. The residue is the alkaloid, which was dried and weighed. Tannin determination by van-burden and robinson (1981) 500mg of the sample was weighed into a 50ml and shaken for 1 hour in a mechanical shaker.
Finally the hexane layer was washed with 100 ml water and then evaporated to dryness with a vacuum rotary evaporator. The concentrated extract was then passed through a chromatographic column (30 cm x 10 mm i.d) containing 2 g florisil (lower) and 1 g sodium sulphate (upper) which is pre wetted with hexane: acetone (1:1). OCPs were eluted with 25 ml hexane: acetone (1:1).The solvent was evaporated using rotary evaporator and final volume was adjusted to 5 ml, which is used for GC analysis. All the sediments were analyzed for HCH and
Mixing .20 milligrams of the commercial dye (red dye #3) with 250 ml of distilled water to get the initial concentration, the goal is basically to get the absorbency level below 1. Putting the dye solution in the blank cuvette and observe the absorbance level that it dorms. Repeat the steps five times making different dilutions to maintain multiple absorbance values. The second week was making another commercial dye solution and also testing the food dye brought into class. Calibrate the spectrophotometer the same exact way so that it does not mess up the calculations gathered.
The reaction mixture contained 100 µl of each of the extract solution in separate tubes (1 mg/ml) to which was added 0.5 ml of Folin-Ciocalteu phenol reagent, 1.5 ml of 20% (w/v) sodium carbonate and 10 ml of distilled water. After 2h of reaction at ambient temperature, the absorbance was measured at 765 nm and used to calculate the phenolic contents, using gallic acid as a standard. All experiments were performed thrice and the results were averaged and reported in the form of mean ± S.D.Then the total phenolic contents were expressed in term of gallic acid equivalents (mg GAE/g dry extract)
Chapter 3: Methodology 3.0 Preparation of Polyaniline 1 0.2 M Aniline hydrochloride was oxidized with 0.25M ammonium peroxydisulfate in an aqueous medium. Firstly, the Aniline hydrochloride was dissolved in distilled water in a volumetric flask to obtain 50mL of the solution. The same step was repeated with Ammonium peroxydisulfate. Both solutions were stored for 1 hour at room temperature and then mixed in a beaker, stirred and left to polymerize. A day later, the PANI precipitate was collected on a filter and washed with three portions of 100mL of 0.2M HCl, and then with the same amount of acetone.
SDS-Polyacrylamide gels were prepared and the glass plates were washed with 70% ethanol and water. After drying the plates, water was used for test leakages. Two SDS-Polyacrylamide gels were prepared according to the following recipe. These all above components of the running gel were added in a 50 ml tube and solutions were mixed and pipetted into the prepared gel chambers. Glass plates were filled ¾ and the gel was covered with 100-500 µl Isopropanol in order to achieve an even surface.