If you have ever worked in a chemistry lab, you are certainly familiar with the fact that measurements are the key factor in doing chemistry. At its heart, chemistry contains some very sophisticated methods that provide us with the products that make our lives easier on daily basis. Specifically, analytical chemistry is the branch of chemical sciences that mainly deals with two parts:
- Qualitative Analysis: Reveals the identity of the chemical species in a given sample.
- Quantitative Analysis: The numerical determination of the absolute or relative abundance of one, several, or all particular substance(s) present in a sample.
Titration, also known as titrimetry, is a form of quantitative analysis that allows chemists to determine unknown concentrations of the particular reagents present in a sample. Since volume is the key parameter of measurement in this analysis, titration is also known as volumetric analysis. The basic process of titration involves the slow addition of one solution of known concentration (called a titrant) to a known volume of another solution of unknown concentration (called analyte) until the reaction reaches neutralization. Knowing the volume of titrant added allows the determination of the concentration of the unknown. Often, an indicator is used to usually signal the endpoint of the titration, indicating that the amount of titrant balances the amount of analyte present, according to the reaction between the two. The first method of volumetric analysis was devised and found by the French chemist Jean-Baptiste-Andre-Dumas as he was trying to determine the proportion of nitrogen combined with other elements in the organic compounds. Nowadays, due to the increase in demand, the classical method of titration in the industrial sector has been replaced by auto-titrators, i.e., machines that progressively feed in the titrant and measure whatever property is used to determine the endpoint. Nonetheless, manual titration is still proved very useful where the cost or need of automation is not justified. For instance, titration in the chemistry lab serves as a bridge between several theoretical concepts and practical operations for the students pursuing chemical sciences or engineering. It gives practice in balancing equations and the relevant mathematics to convert between volume, mass, and mole, which is vital for both disciplines. Although titration may seem a very studious concept, which indeed it is, there are several products we use that would not have been possible without titration. Let’s take a look at few examples of how titration makes our lives easier every day.
1. Food Industry
Making delicious food is undoubtedly a complex task, which comes with a long list of regulations to which the food and beverage industries are strictly subjected. These regulations are fairly reasonable as contaminated food products can cause serious problems to both consumers and producers. Titration is frequently used in the food industry to keep the acid, base, and salt content in the food products under supervision. Some of the everyday food products, whose quality is determined by titration are:
- Acetic Acid in Vinegar, Mayoannies, and Ketchup.
- Citric Acid in Frozen Orange Juice Concentrate.
- Malic Acid in Apple Juice.
- Lactic Acid in Pickles.
- Phosphoric Acid in Cola Beverages.
- Salt in several food products such as Snacks, Chips, Meat Products, etc.
- The alkalinity of Raw Water in the Beverage Industry.
- The nitrogen content as per Kjeldahl (Protein) in meat products.
- The codes of oils and fats, such as acid values, saponification
number, peroxide number, and iodine values.
In determining acidity by titration, the acid is neutralized by an alkaline solution, most commonly, sodium hydroxide (NaOH). In a monoprotic acid titration, equilibrium is reached at a particular pH, which can be detected with a pH meter or visually by adding an indicator that changes its color at the equilibrium pH. With the increase in competition, the level of volumetric analysis in the food industry has reached similar heights to that of the pharmaceutical industry.
2. Cosmetic Industry
Makeup has long been a part of human civilization, with the earliest known use of cosmetic products dating back to 4000 BC (probably by Egyptians). The 21st-century cosmetic industry worth $200 billion in business around the world, and like many other chemical products of our daily use, this industry also depends on titration to a great extent for the quality of their products. Since the product is to be used by the consumer directly on their skin, cosmetic industries need to make sure that the product should not cause any harm to the consumers. Titration facilitates the appropriate concentration and amount of ingredients used in the manufacturing of cosmetic products. Hair dyes, skin creams, shampoos, conditioners, cleansers, and shaving creams all contain some mixtures of acids and bases. For instance, bases like ammonium hydroxide are often used to adjust the pH in these products via titration. Commercially available depilatory creams are of great concern to both the producers and end consumers as they act by entering deep into the skin surface and are most likely to cause allergic reactions such as rashes and bleeding burns. A little misjudgment in the amounts of caustic chemicals can become a major problem, and it can cause the companies to lose millions of dollars in lawsuits.
3. Wine Industry
From vineyards to glass, the process of making wine includes series of chemical reactions and process that guarantees the elegant taste, color, and texture of the wine. For winemakers, the quality of the wine is of paramount importance. Mastering the art of making an exceptional wine comes with the science of titration. For instance, it is essential to measure the concentration of several acids such as tartaric, malic, or citric acid because the acid content impacts the taste, color, and microbial stability of the grape juice from which the wine is to be made. In the wine industry, these acidic concentrations are known by the term “titratable acidity.” The process includes titrating degassed wine with NaOH solution at different paces until the endpoint of 8.2 pH is reached. Another most important step in making wine is to evaluate and control the levels of sulfur dioxide content in the wine. Sulfur dioxide is used as a microbial agent to control the spoilage of wine by destroying bacteria that may cause unwanted secondary fermentation, both during the vintage and winemaking and also during the storage. It also acts as an antioxidant preserving the color of the wine. Sulfur dioxide in wine is traditionally analyzed by Ripper titration using a color indicator. This technique uses iodine and a starch indicator to titrate the solution and determine the concentration of free {SO}_{2}. Although advanced techniques such as gas chromatography or liquid chromatography are usually available to most wineries for practical reasons, titration is critical to ensure the consistency of the product quality.
4. Pharmaceutical Industry
Like many other branches of chemistry, titration has long been a standard method of analysis in the pharmaceutical industry. It facilitates the content determination of active ingredients and raw materials for drug manufacturing. From the formulation of a drug to its production, the role of volumetric analysis can be categorized primarily in four different processes as follow:
- Purity Analysis of Pharmaceutically Active Ingredients: Titration is used to determine the content of active ingredients in pharmaceutical products, e.g. acetylsalicylic acid in Aspirin, or vitamin C in multivitamins tablets, and for the content determination and purity control of drug additives used for the synthesis of medicinal compounds.
- Content Analysis by Redox Titrations: Oxidation-reduction (redox) titrations are also used for checking the purity of raw materials, fillers, and preservatives. A good example of this is the bromatometric determination of methyl- 4-benzoate, a p-hydroxybenzoic acid ester. This compound is used as a preservative in ophthalmic preparations and ointments for external application.
- Precipitation Titrations: Based on their structure, some active ingredients precipitate with a suitable titrant to form consumable medication. Examples of this are benzalkonium chloride and clotrimazole.
- pH-Stat Titrations: The pH-stat titration is performed to characterize drugs, to check the purity of enzyme products, and to investigate the kinetics of chemical reactions. pH-stat means the stationary pH value, i.e. the pH value is held constant for a certain period of time. This technique is used in particular for the determination of reaction kinetic parameters such as the reactivity of enzymes.
Karl Fischer Titration
Karl Fischer Titration is a common analytical method in chemistry that helps in determining the water content in a particular mixture. In the pharmaceutical industry, the water or moisture content of a product plays an important role as far as the activity and the storage lifetime of a product are concerned. Too high or too low water content can impair the effectiveness of the active ingredient over time to a great extent.
5. Biodiesel Manufacturing
With the increase in population and consequent environmental concerns, the demand for renewable resources of energy is also growing day by day. Biodiesel, also known as green diesel, is one of the highly invested alternatives for conventional fuel. It is a form of diesel fuel typically made by reacting lipids such as animal fats, plant extracts, or vegetable oils with an alcohol producing a methyl, ethyl, or propyl ester. The amount of catalyst required to speed up the formation depends on the Free Fatty Acid (FFA) content of the lipids can be determined by using a simple titration method. If the FFA content comes out to be less than one percent, a base catalyst reaction is performed, whereas if the FFA content is more than 1 percent, the acid catalyst is used in the reaction.
6. Wastewater Management
Water is one of the essential components of our life, and its quality and safety are of paramount importance for our well-being. Although water is a renewable resource and is present in abundance on our planet, many developing countries have inadequate access to clean drinking water. To maintain a secure supply of drinking water, reliable testing of key variables is necessary to support wastewater treatment and decontamination processes. The contamination of water is monitored by analyzing the pH level of the water with the help of simple titration methods. A significant change in pH can also have repercussions on the other chemicals present in the water. For instance, under normal conditions, the ammonia present in the water is not regarded as harmful to aquatic life; however, if the pH increases, ammonia becomes toxic and severely affects aquatic life. Besides, the solubility of metals in water also depends upon the pH levels. If the water is more acidic (low pH levels), it tends to dissolve the metals, thus increasing the chances of toxicity. Another factor that titration allows us to analyze is the alkalinity of water. In general terms, alkalinity is the measure of a water body’s ability to neutralize the acid content. Alkaline compounds in the water such as bicarbonates, carbonates, and hydroxides lower the acidity of water by removing {H}^{+} ions.
7. Medical Diagnosis
Medical diagnostic encompasses a wide range of medical test that helps to determine the potential cause of a particular disease. Titration is one of the many practices that lab technicians often come across while analyzing the blood and urine samples from the patients. For instance, titration can allow them to analyze the glucose levels in the blood from a diabetes patient. Another common example of titration in medical diagnostics is the home pregnancy test kits. The urine sample of a pregnant lady contains human chorionic gonadotropin (hCG), which is a hormone chemical produced by the cells in the placenta. Its production starts from the point at which the developing embryo attaches to the uterus, 6-12 days after conception. Whether a woman is pregnant or not is indicated by the appearance of two colored strips on the kit. The titration results may also confirm other problems during the pregnancy, such as vitamin D deficiency.
8. Acid Rain Analysis
Nowadays, one can encounter several impacts of increased acidity of rainwater, such as dissolution of marble and limestone surfaces, corrosion of metal objects, and decreased pH levels of natural waters. This problem is addressed by the term “acid rain” around the world, and it has significant consequences on all organisms. The decreased levels of pH in rainwater result mainly from environmental pollutants such as sulfur dioxide, nitric oxide, etc. Meteorologists make use of titration to analyze the acid content in the rain samples. It is a quick procedure that provides fairly accurate results. Furthermore, titration does not require expensive equipment, which makes it easier for an environmentalist to perform tests frequently in several locations.
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