Determination Of Vitamin C Content Of Tablet Essay

ABSTRACTIn this experiment, the vitamin C content of a commercial digs is conditiond and comp bed with the makers specification. Vitamin C is water-soluble and is an enantiomer of ascorbic superman. (Commercial vitamin C is often a form of ascorbic caustic and other ascorbates.) Ascorbic acid, C6H8O6, is a reducing doer that reacts rapidly with iodine (I2). As the iodine is added during the titration, the ascorbic acid is oxidized to dehydroascorbic acid, while the iodine is reduced to iodide ions as shown in the following equation.Ascorbic acid + I2 (aq) > 2I- (aq) + dehydroascorbic acidDue to this reaction, the iodine create is immediately reduced to iodide as long as there is any ascorbic acid present. The amount of ascorbic acid is determined by the stoichiometry of the equations and the difference between the total amount of iodine present and the amount that reacts with the thiosulphate. This method is suited for use with vitamin C chits, fresh or packaged fruit ju ices and steadfast fruits and vegetables.INTRODUCTIONVitamins ar a group of small seawallcular compounds that are essential nutrients in many multi-cellular organisms, and humans in particular. L-Ascorbic acid was rootage isolated as a pure substance by Albert Azent-Gyorgi and Charles Kingin 1928 (Pauling, 1970), an anti-oxidant and open radical scavenger, is found ubiquitously in fruit and vegetables such as citrus fruit fruits (oranges, lemons, limes, tangerines etc.), melons, tomatoes, peppers, broccoli, green leafy vegetables such as spinach, potatoes and turnips, its quantitative determination is specially in-chief(postnominal) in the p poleuction of wine, beer, milk, soft drinks and fruit juices, where it can be a quality indicator (Gerrior & Zizza, 1994) .Given the essential role vie in the human diet and necessary to growth and freshen up of tissues in all parts of human body .It is necessary to form collagen an important skin proteins ,scar tissue ,tendons, lig aments, and blood vessels. Vitamin C is essential for the healing of wounds, and for the repair and maintenance of cartilage, bones and teeth (Mcevoy, 1993) one of the several ways of determine the ascorbic acid content of a upshot is by titration. encrypt social organization of vitamin c (ascorbic acid)Titration is a strengthtric outline and is one of the basic uninflected techniques in chemistry which enables one to quantitatively determine how much of a specific substance is contained in a given sample. This technique is complex in almost every aspects of our daily living such as life sciences, clinical chemistry, water pollution, industrial analyses etc. In read to make meaningful titration analysis, one has to understand and learn the principles involved. Several types of titration techniques are now available but, two general types which are still in much use are acid-base and drop-off-oxidation (Redox). Acid-base titration involves the neutralization reaction and the products are broadly speaking salt and water. Redox titrations involve the titration of an oxidizing agent (or oxidant) with a reducing agent (or reductant) or vice versa. Oxidation process involves loss of electrons while reduction process involves gain of electrons. Thus an oxidizing agent is one which accepts electrons while a reducing agent is one which loses the electrons. There must be a sufficiently large difference between the oxidizing and reducing capabilities of these agents for the reaction to put up with completion with a sharp end point.MATERIALS AND METHOD250-mL cone-shaped flaskVitamin C tabloids400-mL beakerKBrO2 resolvent50-mL, 25ml and 10ml measuring cylinder10% KI resolvent50-mL burette with stand2.0 M H2SO4 answerGlass stirring rodStarch indicatorAnalytical balanceA. STANDARDIZATION OF SODIUM THIOSULPHATE1. A standard titration setup was framed up using a stand, a burette clamp and a white tileFigure 2 setup for titration(Courtesy of http//www.chemte ach.ac.nz)2. A burette was rinsed with distilled water and because with the given atomic number 11 thiosulphate issue. 3. With the stopcock closed, the rinsed burette was fully filled up with the sodium thiosulphate solvent and then the stopcock was opened so that the tip of the burette was as well allowed to be filled up. The initial burette mess was recorded to an the true of 2 quantitative places 4. A 25.00cm3 pipette was rinsed with distilled water, and then with KBrO3 solution. 5. 25.00cm3 of standard solution of KBrO3 was transferred to a clean conical flask using the rinsed pipette. 6. Using a 25cm3 measuring cylinder, 25ml of 2M H2SO4 was transferred into the conical flask containing the KBrO3 solution. 7. Using a 10ml measuring cylinder, 5ml of 10% KI solution was also added to the conical flask containing the KBrO3 solution. 8. Immediately, the reaction mixture in the conical flask was titrated with the sodium thiosulphate solution until a discolour yellow solutio n was observed. 9. A few drops of starch solution were added to the disturbed yellow solution in the conical flask. 10. Titration of the mixture was continued until the solution changed from dark blue to assumptionless. The final burette reading, accurate to 2 decimal places, was recorded. the stack of the sodium thiosulphate solution added was calculated 11. Apart from the first trial, 2 more successive titrations were carried out. The burette was refilled in between runs when the volume stay was not enough for a complete titration.B. ANALYSIS OF VITAMIN C TABLETSFigure 3 vitamin c tablets(Courtesy of lule.blogspot.com)1. A tablet of vitamin c was transferred into a 250ml conical flask and approximately 40cm3 of 2M H2SO4 was added. The tablet was then crushed to dissolve until a solution formed.2. Using a measuring cylinder, 10cm3 of 10% KI solution was added to the tablet solution and 25cm3 of standard KIO3 solution was pipetted in to the flask.3. The solution was then imme diately titrated with standard thiosulphate solution in the burette until the dark color changed to the original color of the tablet.4. This procedure was repeated with 2 more samples of the tablet.5. The volume of sodium thiosulphate used in each titration was recorded and the average volume was calculated.RESULTS AND CALCULATIONSTRIALSinitial READINGSFINAL READINGSTITRE VOLUMEAVERAGE TITER10.8533.6032.7532.3320.8033.1032.30314.8546.8031.95Table results from standardization of sodium thiosulphate (A) physique of moles of KBrO3 in 25cm3 solution = this formula is used because the molarity of the solution is given and the volume is known 0.009640.025=0.000241molMass of KBrO3 solution used= this formula is used in deriving the mass of a substance when the no. of moles is given (or derived)=0.000241mol167g/mol=0.040247g= 40.25mg submersion of KBrO3 =No. of moles of Na2S2O3 required for one titration = 0.00241mol6= 0.01446molMoles of I2 liberated = 2.4110-4 molesConcentration of Na 2S2O3= 0.298mol/dm3TRIALSINITIAL READINGSFINAL READINGSTITRE VOLUMEAVERAGE TITER18.8011.702.903.43211.7015.203.50315.2019.103.90Table 2 results from vitamin C analysis (B)Brand of vitamin C CenovisManufacturers specification of vitamin c tablet 1000mg of vitamin c per tabletMolar mass of vitamin C (C6H8O6) = 126+18+166=176g/molBalanced Equation for reaction = KIO3+5KI+3H2SO4 3I2+3H2O+3K2SO4Number of moles of KIO3 in 25cm3 solution = 0.00100 molMoles of I2 produced by 25cm3 of KIO3= 0.001003= 0.003 molesNo of moles of Na2S2O3 require to react with excess I2Moles of I2 that reacted with sodium thiosulphateNo. of mole of Na2S2O3 =No. of mole of original I2 no. of mole of excess I2 =0.000723- 0.0005=0.000223molNo. of mole of I2 that reacted with ascorbic acid = 0.006-0.0005 = 0.0055Mass of ascorbic acid = 1760.0055= 0.92g =920mgCONCLUSIONThe experiment was successfully carried out and the results were encouraging. The analysis of the vitamin c content of the Cenovis tablet was carried out using titration. The vitamin c tablet was crushed into a conical flask and specific amounts of KI and KIO3 were added. The solution was then titrated with standard thiosulphate solution until the required color was derived. The results were recorded and calculations to determine the amount of ascorbic acid in each tablet was also successfully done. However the results from the experiment showed different values from the manufacturers specifications. The manufacturer (Cenovis) claims that each vitamin c tablet contains 1000mg of ascorbic acid while this experiment shows otherwise. later on calculations were done, the experiment found each vitamin c tablet to be containing roughly 920mg of ascorbic acid which is below the manufacturers specification. However this error could be as a result of different factors 1. The manufacturer of the tablet do wrong analysis of the tablet. 2. This experiment contained errors which arose from wrong reading of instruments, wrong standard isation of instruments, or errors in uncertainty.Works CitedGerrior, S., & Zizza, C. (1994). Nutrient content of the U.S aliment supply, 1909-1990. Washington D.C U.S department of Agriculture. Mcevoy, G. (1993). Drug information the american hospital pharmacopeia service. American society of health-system pharmacist. Pauling, l. (1970). vitamin c and the common cold.studymode.js. (2010). commercial vitamin c tablet analysis. Retrieved from studymode http//www.studymode.com/essays/Commercial-Vitamin-c-Tablets-Analysis-470526.html