Quantitative Analysis of Vitamin C Contained in Ribena
Title: Quantitative analysis of vitamin C contained in ribena
Aim: to determine the amount of Vitamin C in a sample of ribena
Materials:
* Vitamin C (ascorbic acid, C6H8O6) * 4% potassium iodide (KI) * 1M acetic acid (CH3COOH) * N-bromosuccinimide (NBS, C4H4BrNO2)
Apparatus:
* Conical flask * 100 ml volumetric flask * Weighing bottle * Analytical weight balance * Spatula * Funnel
Results:
Item: | Mass in grams | Mass of weighing bottle with ascorbic acid | 23.4224 | Mass of empty weighing bottle | 23.2883 | Mass of ascorbic acid (C6H8O6) | 00.1341 |
Table 1: Titration of diluted ascorbic acid Titration number: | Rough | 1 | 2 | 3 | 4 | | Final diji reading/mL | 15.00 | 33.70 | 32.50 | 14.60 | 14.50 | ±0.02 | Initial diji reading/mL | 0.00 | 19.20 | 18.10 | 0.00 | 0.00 | ±0.02 | Titre / mL | 15.00 | 14.50 | 14.40 | 14.60 | 14.50 | | Number of OK titres, N | | OK | OK | | OK | 3 | Sum of OK titres | | 14.50 | 14.40 | | 14.50 | 43.4 | Average/ mL | | | | | | 14.47 | Calculations: Concentration of stock ascorbic acid * Mols of ascorbic acid: 0.1341/176 = 7.619 *10^-4 * Concentration = (7.619 *10^-4) / 0.1 = 0.007619 mol/dm3
Concentration of diluted solution of ascorbic acid * V1*M1 = V2*M2 * Concentration = (0.01 * 0.007619) / 0.1 = 7.619*10^-4 mol/dm3 Concentration of NBS * Mols of diluted ascorbic acid: (7.619*10^-4) * 0.01 = 7.619*10^-6 mols * Mols of NBS = Mols of ascorbic acid = 7.619*10^-6 mols * Concentration of NBS: (7.619*10^-6) / 0.01447 = 5.265*10^-4 mols/dm3 Results: Table 2: titration of ribena Titration number: | Rough | 1 | 2 | 3 | | Final diji reading/mL | 16.00 | 15.80 | 31.50 | 15.80 | ±0.02 | Initial diji reading/mL | 0.00 | 0.00 | 15.80 | 0.00 | ±0.02 | Titre / mL | 16.00 | 15.80 | 15.70 | 15.80 |
Aim: to determine the amount of Vitamin C in a sample of ribena
Materials:
* Vitamin C (ascorbic acid, C6H8O6) * 4% potassium iodide (KI) * 1M acetic acid (CH3COOH) * N-bromosuccinimide (NBS, C4H4BrNO2)
Apparatus:
* Conical flask * 100 ml volumetric flask * Weighing bottle * Analytical weight balance * Spatula * Funnel
Results:
Item: | Mass in grams | Mass of weighing bottle with ascorbic acid | 23.4224 | Mass of empty weighing bottle | 23.2883 | Mass of ascorbic acid (C6H8O6) | 00.1341 |
Table 1: Titration of diluted ascorbic acid Titration number: | Rough | 1 | 2 | 3 | 4 | | Final diji reading/mL | 15.00 | 33.70 | 32.50 | 14.60 | 14.50 | ±0.02 | Initial diji reading/mL | 0.00 | 19.20 | 18.10 | 0.00 | 0.00 | ±0.02 | Titre / mL | 15.00 | 14.50 | 14.40 | 14.60 | 14.50 | | Number of OK titres, N | | OK | OK | | OK | 3 | Sum of OK titres | | 14.50 | 14.40 | | 14.50 | 43.4 | Average/ mL | | | | | | 14.47 | Calculations: Concentration of stock ascorbic acid * Mols of ascorbic acid: 0.1341/176 = 7.619 *10^-4 * Concentration = (7.619 *10^-4) / 0.1 = 0.007619 mol/dm3
Concentration of diluted solution of ascorbic acid * V1*M1 = V2*M2 * Concentration = (0.01 * 0.007619) / 0.1 = 7.619*10^-4 mol/dm3 Concentration of NBS * Mols of diluted ascorbic acid: (7.619*10^-4) * 0.01 = 7.619*10^-6 mols * Mols of NBS = Mols of ascorbic acid = 7.619*10^-6 mols * Concentration of NBS: (7.619*10^-6) / 0.01447 = 5.265*10^-4 mols/dm3 Results: Table 2: titration of ribena Titration number: | Rough | 1 | 2 | 3 | | Final diji reading/mL | 16.00 | 15.80 | 31.50 | 15.80 | ±0.02 | Initial diji reading/mL | 0.00 | 0.00 | 15.80 | 0.00 | ±0.02 | Titre / mL | 16.00 | 15.80 | 15.70 | 15.80 |
References: Eitenmiller, R. R., Landen, W. O. & Ye, L.(2008), Vitamin analysis for the health and food sciences, 2nd ed, Boca Raton : CRC Press.