DETERMINATION OF VITAMIN C IN COMMERCIAL PRODUCT

Introduction

Vitamin C, also known as ascorbic acid, is an essential nutrient that plays a vital role in human health. It is a water-soluble vitamin that acts as a powerful antioxidant, protecting cells from damage. Additionally, it is involved in the synthesis of collagen, the absorption of iron, and the maintenance of a healthy immune system. Due to its numerous health benefits, Vitamin C is a commonly added ingredient in various commercial products, including fruit juices, dietary supplements, and fortified foods.

The determination of Vitamin C in commercial products is of great importance to ensure accurate labeling and assess the nutritional content of these products. Analytical methods are employed to quantitatively measure the concentration of Vitamin C present in a sample. One such method commonly used in laboratories is the titration method, which involves the reaction between ascorbic acid and an oxidizing agent, such as iodine. The reaction proceeds in a 1:1 stoichiometry, allowing for the determination of the concentration of Vitamin C in the sample through titration.

In this laboratory experiment, the objective is to determine the amount of Vitamin C in a commercial product by performing a titration. The commercial product chosen for analysis could be a fruit juice or a dietary supplement, both of which frequently claim to contain a specific amount of Vitamin C. By employing the titration method, the experiment aims to accurately determine whether the actual concentration of Vitamin C in the commercial product matches the labeled claim.

Throughout the experiment, several chemical concepts and techniques will be utilized. These include redox reactions, equivalence points, titration calculations, and the use of indicators. Redox reactions are fundamental to this experiment as the reaction between ascorbic acid and iodine involves the transfer of electrons, resulting in the oxidation of ascorbic acid and the reduction of iodine. The stoichiometry of the reaction allows for the determination of the concentration of Vitamin C present in the sample.

Equivalence points, which occur when the number of moles of the titrant is stoichiometrically equivalent to the number of moles of the analyte, will be determined through visual indicators or potentiometric methods. These equivalence points are essential in calculating the concentration of Vitamin C in the commercial product accurately.

Furthermore, titration calculations will be employed to determine the volume of titrant required to reach the equivalence point, allowing for the determination of the concentration of Vitamin C. The use of suitable indicators, such as starch or phenolphthalein, will aid in visualizing the endpoint of the titration, where the color change indicates the completion of the reaction.

In conclusion, the determination of Vitamin C in commercial products is crucial to ensure accurate labeling and assess the nutritional content of these products. By employing the titration method, this laboratory experiment aims to quantitatively measure the concentration of Vitamin C in a chosen commercial product. The experiment will involve the application of chemical concepts, such as redox reactions, equivalence points, titration calculations, and the use of indicators, to accurately determine the concentration of Vitamin C in the sample.

The chemical equation describing the analysis of Vitamin C (ascorbic acid) through the titration method using iodine as the oxidizing agent is as follows:

C6H8O6 (ascorbic acid) + I2 (iodine) + H2O → C6H6O6 (dehydroascorbic acid) + 2 HI (hydroiodic acid)

In this equation, ascorbic acid (C6H8O6) reacts with iodine (I2) in the presence of water (H2O) to form dehydroascorbic acid (C6H6O6) and hydroiodic acid (2 HI). This reaction is a redox reaction, where ascorbic acid acts as the reducing agent and iodine acts as the oxidizing agent. The iodine is reduced to iodide ion (I-) during the reaction.

During the titration process, a known concentration of iodine solution (usually prepared by dissolving iodine in potassium iodide solution) is added to the sample containing ascorbic acid. As the ascorbic acid in the sample reacts with iodine, the iodine is gradually consumed until it reaches an equivalence point, where all the ascorbic acid has reacted. At this point, the color of the solution changes due to the presence of excess iodine, which can be detected using a suitable indicator such as starch or phenolphthalein.

By measuring the volume of iodine solution required to reach the equivalence point, and knowing the concentration of the iodine solution, it is possible to determine the concentration of ascorbic acid (Vitamin C) in the sample through stoichiometric calculations.