A digital burette is an advanced laboratory instrument used for precise and accurate dispensing of liquids in analytical chemistry and other scientific fields. It combines the traditional burette’s functionality with digital technology, allowing for greater control, reproducibility, and ease of use. This document provides a comprehensive overview of the applications of digital burettes in various laboratory settings.
Titration and Analytical Chemistry:
Digital burettes are particularly useful for titration experiments, where accurate measurement and controlled dispensing of reagents are crucial. They allow for the precise addition of titrant to the analyte, ensuring accurate and reproducible results. This is particularly beneficial in acid-base, redox, and complexometric titrations, where even slight variations in volume can impact the endpoint determination.
In pharmaceutical laboratories, digital burettes are employed to dispense precise volumes of solutions during drug formulation, stability testing, and quality control. Their accuracy and repeatability are critical for ensuring consistent product quality and meeting regulatory standards.
Digital burettes play a significant role in environmental testing laboratories, where accurate and traceable measurements are essential. These burettes are used for precise dispensing of reagents during water and soil testing, helping to determine parameters such as pH, conductivity, and various chemical concentrations.
Example: Determining Chloride Content, Calcium Content, Hardness, and Alkalinity of Surface and Ground Water as per ISO 3025 Standards
The chloride content of water can be determined using the argentometric method specified in ISO 3025. The method involves titrating the water sample with a silver nitrate solution in the presence of potassium chromate indicator. The end point of the titration is indicated by the appearance of a reddish-brown precipitate of silver chromate. The chloride content is then calculated from the volume of silver nitrate solution used in the titration.
The calcium content of water can be determined using the complexometric method involves titrating the water sample with a solution of ethylenediaminetetraacetic acid (EDTA) in the presence of a calcium indicator such as murexide. The end point of the titration is indicated by the disappearance of the color of the calcium indicator. The calcium content is then calculated from the volume of EDTA solution used in the titration.
The hardness of water can be determined using the complexometric method involves titrating the water sample with a solution of EDTA in the presence of a buffer solution and a metal ion indicator such as Eriochrome Black T. The end point of the titration is indicated by the change in color of the metal ion indicator. The hardness is then calculated from the volume of EDTA solution used in the titration.
The alkalinity of water can be determined using the titrimetric method specified in ISO 3025. The method involves titrating the water sample with a standard solution of sulphuric acid to a pH of 4.3 using a pH indicator such as phenolphthalein. The endpoint of the titration is indicated by the disappearance of the color of the pH indicator. The alkalinity is then calculated from the volume of sulphuric acid solution used in the titration.
Food and Beverage Industry:
Food and beverage laboratories utilize digital burettes for the accurate addition of solutions during product testing and quality assurance. They are essential in determining acidity, sugar content, and other analytes, ensuring product consistency and compliance with industry standards.
Example: Determining Free Fatty Acid as per ISO Standards
Free fatty acids (FFA) are a quality feature of plant oils and fats, such as edible oils and fats. Fats with high levels of FFA are more susceptible to oxidative aging and become rancid more quickly. The FFA should be removed during a refining process. The determination of FFA in oils and fats is done by potentiometric titration in Ethanol/Diethyl ether as a solvent with KOH in Isopropyl alcohol
- Weigh a sample of the oil or fat into a 150 ml glass beaker.
- Add 70 ml of the solvent mixture (500 ml absolute Ethanol and 500 ml Diethyl ether mixed in equal parts).
- Heat the mixture to increase the solubility of the oil/fat, especially with solid fats (e.g. coconut fat).
- After complete dissolution, titrate the sample with 0.1 mol/l KOH.
- The sample weight should be selected so that the titration amount is not more than 4-5 ml because of the long titration time.
- The required amount of sample depends on the expected Acid number (mgKOH/g).
- The result is calculated as mg(KOH)/g or as %fatty acid (mainly as %oleic acid with Moleic acid = 282.47 g/mol).
To conclude, determination of free fatty acid in oils and fats is done by potentiometric titration in Ethanol/Diethyl ether as a solvent with KOH in Isopropyl alcohol, as per ISO standards. The method is suitable for edible fats and oils such as butter, olive, palm, or sunflower oil.
Education and Research:
Digital burettes are valuable tools in educational institutions and research settings. They simplify the process of teaching and learning about titration techniques, helping students understand fundamental concepts of analytical chemistry. In research, digital burettes aid in experiments where precise reagent additions are required, contributing to reliable and reproducible outcomes.
Electroplating and Surface Coating:
In industries that involve electroplating and surface coating, digital burettes are used for accurately dispensing plating solutions and coating materials. This ensures consistent and uniform coatings on various substrates.
Example in Determination of acid and copper concentrations in electroplating and coating industries: concentration of sulphuric acid can be indirectly determined by titration with a standardized solution of a base, such as sodium hydroxide (NaOH), using phenolphthalein as an indicator. The volume of the base solution required to neutralize the acid can be used to calculate the acid concentration the determination of acid and copper concentrations is crucial for ensuring the quality and performance of the plating processes