Introduction: Vitamin C, also known as ascorbic acid, is an important vitamin for a healthy diet. It is important in the growth and repair of tissue, skin, wounds, bones and teeth. It is also an antioxidant. Vitamin C is found in fruit juice and to discover how much vitamin C is in fruit juice, a titration can be performed. A titration is a lab method used to determine an unknown concentration of a solution by adding a reagent with a known concentration. The main goals of this experiment were to perform a redox titration and improve titration technique, to become familiar with the redox reactions with organic molecules, and to determine the amount of vitamin C in a sample of fruit juice.
Experimental: Part 1 of the experiment was the standardization of the Iodine solution. First, three ascorbic acid samples were weighed out to 0.10 grams each and then placed into a 250mL Erlenmeyer flask. Each flask containing the sample was then filled with 100mL of distilled water and the ascorbic acid dissolved. Next, 100 mL of the stock I2 solution was measured into a 400mL beaker and 150 mL of water was added and thoroughly stirred. A buret was obtained, washed thoroughly, and then rinsed three times with the I2 solution. Then the buret was filled with the I2 solution. 1 mL of starch indicator was added to the first ascorbic acid sample. An initial reading on the buret was recorded and then the titration began. The flask was gently swirled to mix the solution as the titration was
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In this experiment redox-based titrimetric analysis was used to determine the amount of ascorbic acid (Vitamin C) contained in a serving of lemonade. This was done to confirm the 100 percent recommended daily allowance claimed on the package for a serving of Country Time Lemonade. The titration method used was adding a thyodene indicator to the analyte (lemonade solution) there is a visible colour change when the endpoint of the reaction between the titrant (KIO3) and the analyte occurs. The following reactions show how this titration method is viable. (Draw in reactions) KIO3 first reduced with iodide (I-) to generate iodine (I2 ) which then oxidized the ascorbic acid within the lemonade. Once all the ascorbic acid had reacted any iodine
A few crystals of potassium iodide was added to the flask and then swirled to dissolve the solid potassium iodide. The volume of the liquid in the buret was read. The liquid in the buret was titrated with the thiosulfate solution until the brown color of iodine had disappeared. Afterward, 1 mL of starch solution and then thiosulfate solution was added until the blue color of the starch-iodine complex disappeared. The volume of the liquid in the buret was read again. Also, a large test tube was cleaned and dried. 50 mL of iodine solution was carefully measured with a 25 mL graduated cylinder. Next, 5.0 mL of cyclohexane was measured and added to the graduated cylinder. The test tube was stoppered with a rubber stopper. The mixture was shook for one minute at first, then for about five minutes. The process was repeated, where the 50 mL of iodine solution in a 25 mL graduated cylinder was obtained, and then a second 50 mL of iodine solution and 8.0 mL of cyclohexane was added. Next, the cyclohexane layer was removed with a Pasteur pipet from the first test tube into a beaker. In addition, 25.0 mL of the water layer was poured into a clean,
The first thing that should be done when starting this lab is to write down observations on the materials that will be used in this experiment. After having written down the observations begin the lab by placing (without using your fingers) 2 small pieces of solid iodine into a small test tube that contains 1mL (20 drops) of water. Make sure to mix and crush with a stirring rod while commenting on how well the iodine is dissolving. Compare how well it dissolves in water by comparing how iodine dissolves in alcohol, mineral oil and a solution of potassium iodide. After doing that the solubility of zinc in water should be also checked by adding a few pieces of granular zinc into 1mL of water and then comparing how well it dissolves in water by
For every two moles of thiosulphate, one mole of iodine is needed so the amount of iodine mole needed is half the amount of thiosulphate moles that are needed. Starch is used as the indicator for the end point because the iodine and water is such a faint yellow color that the starch will combine with any of the iodine that is still present and turn it a blue color and the end point for the titration is than easier to notice.
50µL of iodine will be equally added into each micro plate. • Amount of starch and amylase mixture. 5ml of starch solution and 500µL of enzyme solution composed of amylase and pH buffer. • Temperature. The experiment will be maintained in the lab at temperature (30°C)
HOW TO MEASURE THE ASCORBIC ACID CONTENT OF ORANGE JUICE A. A Fill a test tube with 10mL of indophenol. B With an eyedropper get some of the orange juice that is being tested. C One drop at a time, add the juice into the indophenol.
One of the drawbacks of using iodine is its low solubility in water, as well as its potential staining of teeth. One path to overcome these disadvantages is changing the drug delivery of iodine. Iodine complexed with polyvinyl pyrrolidone(PVP),to form povidone-iodine(PI), increase water solubility, decrease irritation and decrease the staining caused by pure iodine.(13)
Vitamin C also known as ascorbic acid is needed for growth and maintenance of healthy tissues, especially skin, blood vessels, bones, gums, teeth. Vitamin C aids in resistance against infection and healing of wounds. It also helps the body absorb iron from food. Vitamin C can be found in green vegetables, potatoes, tomatoes and citrus fruits such as oranges and lemon. A lack of vitamin C can cause scurvy, iron deficiency and poor wound healing. A healthy diet
My fourth report will be on the medical use of iodine. I will specifically focus on Iodine as a sterilization agent for surgeries or wounds in health care. Iodine is a chemical element used often in disinfectant found in the OR suite of a hospital.
Added 300 ml of water to 400-500 ml beaker than added several drops of I2KI (iodine potassium iodide). until the water was visibly yellow. I2KI Than placed bag into the beaker for 30 minutes. Finally, the last procedure of this lab was the benedicts test this is commonly used to detect presence of reducing sugar. First they had to label 3 test tubes control bag and beaker, they added 2 pipettes of water for the control tube, 2 pipettes of the bag solution, and two pipettes of the beaker solution and added 1 drop of benedicts reagent to each tube.
The value of 82.5mg per 250mL serving will then be divided by 10 in, order to have the serving size to be equal to that of the experiment (25.0mL), resulting in the amount of Ascorbic Acid in the juice to be 8.25 mg, which is less than the observed and calculated value of 10.73mg. Thus there appeared to be random error within the
In this experiment, we are going to find out which fruit juice provides the most amount of vitamin C. We will use a blue substance called 2, 6-dichlorophenolindophenol (or DCPIP for short) as a reagent to test for vitamin C. It acts as an indicator where it changes from blue to pink with acids but loses its color in the presence of certain chemicals, one of which is ascorbic acid (vitamin C). DCPIP solution can be used to test for the presence of vitamin C in foods (but not for other vitamins which are entirely different kinds of chemical). It is an electron acceptor that is blue when oxidized and colorless when reduced. It is part of the Hill reagents family. DCPIP is commonly used as a substitute for NADP+. The dye changes color when it is reduced, due to its chemical structure. The nitrogen atom in the center of the molecule is the atom that accepts electrons, and it changes the double N-C bond to a single bond, which forces bonds between carbons in the entire left ring to change. This microscopic shift in the DCPIP structure causes the macroscopic change in color, from dark blue to colorless. If vitamin C, which is a good reducing agent, is present, the blue dye, which turns pink in acid conditions, is reduced to a colorless compound by ascorbic