Руководство «Титрование от А до Я в теории и на практике»

Titration is an analytical technique which allows the quantitative determination of a specific substance (analyte) dissolved in a sample. It is based on a complete chemical reaction between the analyte and a reagent (titrant) of known concentration which is added to the sample:

Analyte + Reagent (Titrant) = Reaction Products

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From manual to automated titration

The classical way to perform a titration is using a graduated glass cylinder (burette). With a tap the titrant addition is regulated manually. A change in color indicates the end of the titration reaction (endpoint).

Titration has experienced a strong development: manual and later motor-driven piston burette…

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Titration is a widely applied analytical technique used in various fields.

A few examples are given below:

• Food & beverages

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To learn more about Sodium content determination in Food & Beverages download our free applications brochure

There are several reasons why titration is used in laboratories worldwide. A comparison of manual and automated titration is shown below:

Download the ABC of titration guide to learn more about the titration theory

Titrations can be classified according to the chemical reactions occurring and the indication principles used to monitor the reaction.

•  5.1 Types of chemical reaction

Mainly three different kinds of chemical reactions are used in titration. The reactions are listed below with an example and some typical applications

Acid/Base reactions:

HCl + NaOH    ↔     NaCl  + H₂O

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To get to know the others chemical reactions and much more download the ABC of titration

• 5.2 Indication principles
  • 5.2.1 Manual titration
  • 5.2.2 Semi or automated titration
• 5.3 Titration Mode – Endpoint / Equivalence point
  • 5.3.1 Endpoint titration (EP)
  • 5.3.2 Equivalence point titration (EQP)
• 5.4 Titration types
  • 5.4.1 Direct titration
  • 5.4.2 Blank compensated titration
  • 5.4.3 Back titration

A manual titration is controlled by the operator himself. The titrant addition is regulated manually and the monitoring of the reaction and indication of the endpoint are mostly done visually.

Download the "Titration at a Glance" poster helps the manual titration user in his daily tasks with titration information

• 6.1 Manual titration
• 6.2 Automated titration
  • 6.2.1 Titrant addition
  • 6.2.2 Measured value acquisition

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The calculation of the final result is based on the consumption of the  titrant as well as the stoichiometry of the chemical reaction between analyte and titrant.

• 7.1 Stoichiometry and equivalent number
• 7.2 Result calculation

Download the ABC of titration guide to learn more about the titration theory

• 8.1 Titrant
  The titrant is a solution of a certain reagent with known concentration which reacts with the analyte in the sample. Its nominal concentration is usually expressed in…
  
  • 8.1.1 Titrant concentration determination
• 8.2 Sensor
  •  8.2.1 pH sensor and measurements (Acid/Base titrations)
    • 8.2.1.1 pH Sensor and Temperature

Download the ABC of titration guide to learn more about the titration theory

Performance verification is achieved by a standard titration of a reference sample with a known content. Hereby the entire titration procedure including.

Download the ABC of titration guide to learn more about the titration theory

The Karl Fischer method for water content determination is one of the most frequently used titration methods.

The titration is based on the reaction described by R. W. Bunsen:

I₂ + SO₂ + 2 H₂O → 2 HI + H₂SO₄

Karl Fischer, a German petro-chemist, discovered that the reaction…

Download the ABC of titration guide to learn more about the titration theory

• 10.1 Titration principle
• 10.2 Endpoint indication of a Karl Fischer titraton
• 10.3 Prerequisites for voulometric Karl Fischer titration
• 10.4 Drift
• 10.5 Volumetric Karl Fischer reagents
  • 10.5.1 One-component KF reagent
  • 10.5.2 Two-component KF reagent
• 10.6 Concentration determination
• 10.7 Sample handling
  • 10.7.1 Solid samples
  • 10.7.2 Liquid samples
  • 10.7.3 Solubility of sample
• 10.8 Execution of a volumetric Karl Fischer titration
• 10.9 Interferences of Karl Fischer titration
  • 10.9.1 Influence of pH
  • 10.9.2 Side reactions