What Is Titration?

Titration in Chemistry: A Comprehensive Overview of Titration Techniques, Applications and Methods

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Titration explained: This video shows the basics of titration theory and details the advantages of modern titration systems
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Acid-Base Titration

A titration of acids and bases assesses the point at which an acid and a base mixed into a solution are neutralized. As such, an appropriate pH indicator is added to the titration chamber. The indicator in an acid-base titration changes color when the endpoint is reached. Because the reaction’s endpoint and equivalence point are not identical, careful selection of titration indicators will reduce errors.

Back Titration

Essentially, back titration is a titration done in reverse. The person performing the titration does not titrate the original sample; instead, they add a known excess of standard reagent to the solution, with the excess then being titrated. Back titrations are useful if the reaction between the analyte and titrant is very slow, when the analyte is a non-soluble solid, or the endpoint of a reverse titration is easier to identify than the endpoint of the normal titration, as with precipitation reactions.

Complexometric Titration

Complexometric titrations form a complex between an analyte and titrant. Generally, these titration reactions require indicators that form a weak complex with the analyte. Perhaps the most common complexometric titration example is the use of a starch indicator to increase the sensitivity of iodometric titration to produce a more visible color change. Complexometric indicators include the chelating agent EDTA, which is used to titrate metal ions in solution, and Eriochrome Black T for the titration of calcium and magnesium ions.

Gas-Phase Titration

Gas-phase titrations determine reactive species using an excess of another gas as the titrant. After reaction, the remaining titrant and product are quantified to determine the amount of analyte in the original sample (for example, using Fourier-transform infrared spectroscopy, or FTIR). Gas-phase titration has certain advantages over simple spectrophotometry, including independence from path length and its usefulness measuring samples that contain species that typically interfere at wavelengths used for the analyte.

Karl Fischer Determination

This specific titration, which is also known as KF titration, is a classic method used to determine trace amounts of water in a sample. Coulometric titration is used for low water content determination (water contents as low as 1 ppm to 5%), whereas volumetric titration is used to determine water content from 100 ppm to 100%. For more on this specialized titration technique, visit our library of Karl Fischer determination guides.
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Potentiometric Titration

In potentiometric titration, the concentration-dependent potential (mV) of a solution is measured against a reference potential. In practice, potentiometric titration bears similarity to a redox reaction. However, potential is measured across the analyte — typically an electrolyte solution — using reference and indicator electrodes. Hydrogen, calomel, and silver-chloride electrodes are often used for the reference, while a specialized titration electrode forms an electrochemical half-cell with the interested ions in the test solution.
For more information on potentiometric titrations, related titrators and routine applications, visit our page on Potentiometric Compact Titrators designed to cover your routine application needs.

Redox Titration

Redox titrations measure a reduction-oxidation reaction between an oxidizing agent and a reducing agent. End-point determination may be made using a potentiometer or a redox indicator if color change is not definitive (as when one of the constituents is potassium dichromate). Analyzing a wine for sulfur dioxide requires iodine for oxidation; therefore, starch is used as the indicator (which forms a blue starch-iodine complex in the presence of excess iodine). However, color change is often a sufficient endpoint indicator.

Zeta Potential Titration

Titrations in which completion is monitored by the zeta potential, rather than a titration system indicator are known as zeta-potential titrations. These titrations are used to characterize heterogeneous systems including colloids. One use is determining the point at which a surface charge becomes zero by changing the pH or adding surfactant. Another is to determine an optimum flocculation or stabilization dose.

For more information on titrators that are expandable for a broad range of titrations and applications, check out our modular titrators.

Manual titration
Automated titration

A titration end point curve: Titrant has been added until the endpoint of the titration reaction is observed.

titration end point curve
titration end point curve

An equivalence point titration curve: The point at which analyte and reagent are present in equal amounts is identified.

equivalence point titration curve
equivalence point titration curve

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Titration applications

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