Determination of peroxide value by titration. How to Measure Peroxide value using autotitrator 2022-10-19
Determination of peroxide value by titration Rating:
Peroxide value is a measure of the concentration of peroxides in a substance, typically an oil or fat. Peroxides are compounds that contain an oxygen-oxygen bond, and they can be harmful to both human health and the stability of the substance in which they are present. Therefore, it is important to determine the peroxide value of oils and fats in order to ensure their quality and safety.
One way to determine the peroxide value of a substance is through titration. Titration is a laboratory technique in which a known concentration of a reagent, called the titrant, is added to a sample until a chemical reaction is complete. The volume of titrant needed to complete the reaction is then used to calculate the concentration of the substance being measured.
To determine the peroxide value of an oil or fat using titration, a sample of the substance is first placed in a flask or beaker. An indicator solution, such as potassium iodide, is then added to the sample. The indicator solution reacts with the peroxides in the sample to produce iodine, which changes the color of the solution.
Next, a standardized solution of sodium thiosulfate, also known as a titrant, is added to the flask or beaker. The sodium thiosulfate reacts with the iodine to produce a colorless solution. The volume of sodium thiosulfate needed to fully react with the iodine is measured using a burette, a precision instrument used to measure the volume of a liquid.
The peroxide value of the sample is then calculated using the following formula:
Peroxide value (meq/kg) = (Volume of sodium thiosulfate needed / Sample weight) x Normality of sodium thiosulfate
The normality of the sodium thiosulfate is a measure of its concentration, and it is typically provided with the standardized solution. The sample weight is typically measured in kilograms.
It is important to note that the peroxide value determined through titration is a measure of the concentration of peroxides present in the sample at the time of the analysis. Peroxides can continue to form over time, so the peroxide value of an oil or fat can change over its shelf life. Therefore, it is important to regularly test the peroxide value of oils and fats to ensure their quality and safety.
In conclusion, the determination of peroxide value by titration is a useful and precise method for measuring the concentration of peroxides in oils and fats. This information is important for ensuring the quality and safety of these products and can help to protect the health of consumers.
Determination of Hydrogen Peroxide Concentration
Calculate the mean, standard deviation and relative standard deviation for your data. But the correct H 2O 2 concentration must be ensured due to the fact that is a very unstable molecule. In this experiment hydrogen peroxide will oxidize the iodide ion, IP-P, obtained from potassium iodide to iodine, IB2B. Using Redox Titration for the Determination of Hydrogen Peroxide in Sanitizers. This means that if we know how much the number of moles thiosulphate we need to react with the iodine we can calculate how much hydrogen peroxide was in the solution we started with. The peroxide value is the number of milliequivalents of active oxygen that expresses the amount of peroxide contained in 1000 g of the substance.
Hydrogen peroxide, HB2BOB2B is readily available in supermarkets and pharmacies since it is a principal component in bleaches for hair and most recently and controversially it was one of the components used to make the bombs which exploded in London on 7PthP July 2005. » 1% Starch Solution. Cox, H E and Pearson, D 1962 The Chemical Analysis of Foods Chemical Publishing Co Inc New York p 421. Swirl the flask in order to dissolve the potassium iodide in the sulphuric acid. Calculate a value for the concentration of the hydrogen peroxide solution for your best three titrations.
The iodine solution should now be much darker — almost black. Optimizing the method parameters as per sample may be necessary for the best results. The experiment is quite short and so you have plenty of opportunity to repeat the titrations until you get consistent results. Based on the sample solubility, different solvents can be used such as acetic acid: chloroform, acetic acid: cyclohexane and acetic acid: isooctane in various proportions described in the application note. THEORY Titrimetry, or titrimetric analysis, is an example of a so-called classical method of analysis. Get Expert Help at an Amazing Discount! The titration is relatively easy to follow because the iodine produced by reaction of hydrogen peroxide with iodide is iodine, which is purple in colour. In this experiment you will use a titrimetric method to determine the amount of hydrogen peroxide in a given solution.
Using Redox Titration for the Determination of Hydrogen Peroxide in Sanitizers
This shows that 1 mole n2 HB2BOB2B is equivalent to 2 n1 moles thiosulphate mole ratio. Peroxides are also thought to contribute to aging of skin and they are also a source of free radicals thought to be partly responsible for some cancers. Hydrogen peroxide can act as both an oxidizing agent and a reducing agent depending upon the conditions of the reaction. » 5% Potassium Iodide Solution. Note: we have omitted the potassium ion, KP+P, from this reaction since it would occur on both sides of the equation and so it does not take part in the reaction. Titrimetry is a convenient method of getting very small amounts of chemicals in to a reaction because the method involves the use of dilute solutions of reactants.
[Solved] The Determination of Hydrogen Peroxide by Iodometric Titration.
You are provided with a solution of hydrogen peroxide and a solution of sodium thiosulphate as well as 1. Therefore it is very important to test these oils, fats and margarines for their purity with a precise, accurate and a convenient method. Hydrogen Peroxide is used in a large variety of applications and industries as its consumption creates only oxygen and water, which is environmentally friendly. Comment on your results. Oxidative rancidity in oils and fats is one of the major factors affecting the quality of these foods.
You are provided with a solution of hydrogen peroxide and a solution of sodium thiosulphate as well as 1. Weigh 1g of oil or fat into a clean dry boiling tube and add 1g of powdered potassium iodide and 20mL of solvent mixture. Run some of this solution through the burette to remove any bubbles below the tap. Wash the tube twice with 25mL water each time and collect into the conical flask. Solutions range from receiving raw materials, in-line process control and end-of-line packaging control, to logistics and shipping. Addition of thiosulphate solution gives a colourless solution when all of the iodine has reacted the end point. Sponsored Content Policy: News-Medical.
Throughout your experiment, note any colours that are observed in your lab book. EXPERIMENTAL In this experiment you will use titrimetric analysis to determine the concentration of hydrogen peroxide in a solution. Carry out a blank titration omitting the substance under examination b ml. Source: Mettler Toledo - Titration Disinfectant R1:Content, % Sanitizer R1: Content, % 1 2. Combining equations 1 and 2: 1 mole HB2BOB2B gives 1 mole iodine AND 1 mole iodine reacts with 2 moles thiosulphate. Titrant: Cerium sulfate, Ce SO 4 2, 0.
The Determination of Hydrogen Peroxide by Iodometric Titration.
You can add the thiosulphate fairly quickly in the early stages but you will need to add the thiosulphate more slowly as the colour of the iodine get more and more yellow. Using Redox Titration for the Determination of Hydrogen Peroxide in Sanitizers. Addition of thiosulphate solution gives a colourless solution when all of the iodine has reacted the end point. The Determination of Hydrogen Peroxide H 2O 2 concentration is crucial to product quality control. Swirl the flask in order to dissolve the potassium iodide in the sulphuric acid.
You can make the end point even sharper by adding a few drops of starch solution when the colour of the solution is pale yellow. In oxidative rancidity oxygen is taken up by the fat with the formation of peroxides. Record the reading on the burette again to the nearest 0. Many different techniques can be used to determine H 2O 2 concentration, such as titration. The starch changes the colour of the solution to black but the solution will become colourless at the end point. A blank should also be set at the same time.