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Titration is used in analytical chemistry to determine the amount or

concentration of a substance, known as the analyte. Titration is a

quantitative measurement of an analyte in solution by its complete

reaction with a reagent. In a titration, one reagent (the titrant) is

slowly added to a solution containing the species being measured

(the analyte). As it is added, a chemical reaction occurs between the

titrant and analyte. The point at which the reaction is complete and an

equivalent quantity of titrant and analyte are present (a stoichiometric

equivalent) is called the equivalence point. This can be determined

by a chemical indicator that is also present in the solution, or by a

measurable physical change in the solution, like pH, electrode potential,

conductivity, or light absorption (color). In practice, an abrupt change of

this physical property signals the end of titration, called the endpoint.

The purpose of titration is to determine the quantity or concentration

of an analyte with a known concentration and volume of a titrant.

Titrations are based on chemical reactions which must fulfill four

requirements:

• The reaction between the analyte and the titrant

must occur quickly, without a secondary reaction

• The reaction must go to completion

• The reaction must have well-known stoichiometry (reaction ratio)

• Must have a convenient method of endpoint detection

Titrations are highly precise and can provide many advantages over

alternative methods. Titrations are quickly performed and require

relatively simple apparatus and instrumentation.

Automatic Titration

Automatic titration is done with instrumentation that delivers the

titrant, stops at the endpoint and calculates the concentration of the

analyte automatically. Automatic titrators are best for accurate and

repeatable results, as an electrochemical measurement is used to

determine the endpoint as opposed to a subjective color indicator.

Analyses that can be performed by potentiometric automatic

titrators include:

• Acid-base titrations

• Oxidation reduction titrations

• Complexometric titrations

• Precipitation titrations

• Non-aqueous titrations

• Argentometric titrations

• pH, ORP and Ion selective measurements

Analyses performed by bivoltammetric automatic titrators include:

• Coulometric Karl Fischer titration (trace

amounts of water determination)

• Volumetric Karl Fischer titration (greater

than 100 ppmwater determination)

Hanna Instruments

Titration Systems

Titration

4.2

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