Complexometric Titrations Applied in Pharmaceutical Analysis

The technique that involves the titration of metal ions along with a complexing agent or ligand, which is a chelating agent, is generally known as complexometric titration. The systematic submission of complexometric titration is represented in this method. During this process, a simple type of ion is changed into a composite ion and the point of equivalence is decided by using indicators of metals or by the electrometrical process. There are other names used to describe this method, such as EDTA titration, chilometry or chelometric titration. All the names used to describe this are systematic methods used in this analysis.

Complexometric Titration

Complexometric titration is a type of volumetric analysis where a newly formed coloured complex is utilised to show the titration’s endpoint. It is specifically considered very useful since it is used in the mixing of different metal ions in a solution. Any indicator which is used to produce a definite colour change usually helps in detecting the titration’s endpoint.

Types of Complexometric Titration

In complexometric titration, ethylenediamine tetraacetic acid (EDTA) can be used as a solution since its concentration is called titration. Some of the ways it can be used are discussed below:

Direct Titration

This is one of the simplest methods compared to all other methods used in complexometric titration. Direct titration is very similar to the technique of acid-base titration. In this, EDTA is added to samples which have metals using burette until the endpoint is reached. Some of the metals are resolute by using the direct way of complexometric titration.

Back Titration

To achieve the excess amount of EDTA, back titration is required. In this type of titration, a high amount of EDTA solution is added to the solution of metal, and it is examined later. After that, the high amount of EDTA is then titrated back by the second metal’s ion solution.

Replacement Titration

When the endpoint is not achieved using direct titration and back titration, replacement titration is used to get the sharp endpoints. The analyte which contains the metal is then added to the metal of the EDTA complex.

Indirect Titration

There are some anions that form a precipitate with the metal cations. They usually do not have any reaction to the EDTA. That is the reason they are known as indirect titration with EDTA. For example, barium ions can be under indirect titration.

Examples of Complexometric Titration

Ethylenediamine tetraacetic acid or EDTA is an indicator of a complexometric system which has two amino groups and four carboxyl groups known as the Lewis bases. Hexadentate ligand has the competency to denote the six pairs of the lonely electrons, due to the formations of the covalent bonds.

Necessity of Complexometric Titration in Pharmaceutical Analysis

In pharmaceuticals, titration is very important as it reduces the adverse effect of drugs on the body. So, the process of titration becomes very important as people of different body types, age groups, and diseases respond differently. By using titration, a medical doctor can also slowly adjust the dosage to the person to ensure there are no adverse effects.

Conclusion

Complexometric titration is a type of volumetric analysis where a newly formed coloured complex is used to show the titration’s endpoint. There are four different types of complexometric titration:

• Direct titration is one of the simplest methods among all methods used in complexometric titration

• Where there is an excess amount of EDTA, back titration is required

• When the endpoint is not achieved using the direct titration and back titration, replacement titration is used to get the sharp endpoints

• In indirect titration, there are some anions that form a precipitate with the metal cations