Concentrate the methylene chloride solution of benzyl alcohol by using distillation assembly placed in a water bath, until the volume of the residual liquid reduced to half volume. 4. Cool the remaining liquid, transfer it to a separatory funnel and shake it thoroughly with two 1 mL portions of 20% aqueous sodium bisulfite to remove any benzaldehyde. Wash the methylene chloride solution finally with two 1 mL portions of water and dry it with 0.5-1 g of anhydrous magnesium sulfate. 5.
If any spattering occurs while heating, wash the solid back down into the solution using a wash bottle. Heat the solution until all the blue solid has been decomposed to the dark colored copper(II) oxide. Allow the mixture to cool before filtering. Fold a piece of the Whatman filter paper while waiting for the mixture to cool. To fold the Whatman paper, you first fold it in half, and then in half again.
Cool to room temperature and add water to make up to 200 ml and filter the contents after shaking. Take 100ml of the filtrate and add 6ml of nitric acid and a few drops of ferric ammonium sulphate indicator. 7. Titrate the solution with standard ammonium thiocyanate solution until a permanent red colour is
3.7.3 Benedict’s Test 1mL of the filtrate was added to 5mL of Benedict’s reagent and then the mixture was heated. Positive result: appearance of red precipitate indicated the presence of reducing sugars. 3.8 Test for Proteins 2g equivalent of the plant extract was evaporated and the residue was taken up with 10mL of water. 3.8.1 Millon’s Test 10 drops of Millon’s reagent was added to the 1mL of aqueous extract and placed into a boiling water bath. Positive result: presence of flesh color.
Glass plates were filled ¾ and the gel was covered with 100-500 µl Isopropanol in order to achieve an even surface. When the gel was polymerized, isopropanol was removed on the top of the running gel with water and thus, water was also removed as well. Then, stacking gel was prepared and its polymerization reaction was started with TEMED, and its solution was quickly poured on the top of the running gel. Therefore, a comb was inserted into the stacking gel before its polymerization, to form the loading wells. When the gel was polymerized, the inner chamber was filled with electrophoresis running
* The above procedures were modified from the "Background on Making Soap and Detergent" on Lab Achieves. In week 2's experiment for HCl standardization 0.2 g of Na2CO3 was weighed and dissolved into an Erlenmeyer flask filled with 50 mL distilled water. 4 drops of Phenolphthalein were added to the solution and the color was recorded. The solution was titrated with HCl until just before the endpoint (when the solution is very light pink). Solution was cooled to room temperature and the sides of the flask were washed with small amounts of distilled water to get all of the sample back into the solution.
The reaction mixture was then cooled and poured into crushed ice with constant stirring and left overnight. A dark red coloured copolymer was obtained and washed with warm water, methanol and acetone followed by filtration to remove unreacted monomers and impurities. Finally, the copolymer was dried in an air oven at 75 °C for 24 h. The yield of the copolymer was found to be 85%. The copolymer was found to be soluble in solvents like dimethylsulphoxide, dimethylformamide and tetrahydrofuran and partially soluble in mineral acids. The mechanism of the synthesis of copolymer (SFP) is shown in Scheme
Take a clean dry gel casting plate and make a gel mould using an adhesive tape along the sides of the plate to prevent running off of the material to be poured on the plate 2. Pour 50 ml of 1% agarose solution kept at 50ºC onto the casting plate. Immediately place the supplied comb about 1 cm from one end of the plate ensuring that teeth of the comb do not touch the glass plate. Wait till a firm layer of gel is formed. 3.
After staining the CV solution was removed and every well was washed twice with distilled water. Finally, the CV that remained associated with the biofilm was solubilized with 200 µl of an ethanol-acetone solution (80 % v/v and 20 % v/v respectively) and the absorbance at 590 nm of the resulting solution was determined. For each strain, three independent experiments with four replicates each were
Weigh the flask and slurry, Wfs. Carefully fill flask/bottle about three-quarter full with deaired distilled water. Remove any air entrapped by applying partial vacuum to the slurry. In some cases, you may need to boil the contents for about 10 minutes and reapply the partial vacuum. Now add distilled water to fill the flask to the bottom meniscus at the calibration mark.