Applications of non-aqueous titration

Using non-aqueous titration, the concentration of an unknown acid or base in a non-aqueous solution can be determined. It can also be used to identify the equivalence point of a non-aqueous solution reaction between an acid and a base.

Non-aqueous titration is a type of titration in which the analyte is dissolved purely in a non-aqueous solvent (does not contain a water molecule). Acid or base is used as a titrant to perform this titration. In a weakly acidic or basic medium, aqueous solvents quickly accept or donate protons. For this reason, the titration method needs to use non-aqueous solvents to get accurate and precise endpoints. The use of non-aqueous titrations in pharmaceutical assays is one of the most common applications for this technique.

Analysis of non-aqueous titration is based on the Bronsted-Lowry theory, in which the following are two of the most important reasons that the non-aqueous titration theory satisfies:

• Suitable for titrations of weak acid and base
• An appropriate solvent medium is used to dissolve organic compounds

Hence, non-aqueous solvents such as acetones and alcohols replace water in titrations since they do not compete with other analytes for proton donation or acceptance.

In the non-aqueous titration of a particular analyte, four types of solvents are commonly used.

1. Aprotic solvents-(Chloroform and benzene)
2. Protophilic solvents-(Acetic and acid sulphuric acid)
3. Protogenic solvents-(Amines liquid and ammonia)
4. Amphiprotic solvents-(Acetic acid and alcohols)

Here is an example of a reaction for which water is not a suitable solvent:

R-NH2 + H+ ⇌ R-NH3+

When carried out in an aqueous solvent it is completed by the following reaction:

H2O + H+ ⇌H3O+

A weak base or acid can be the organic solvent. The titration is conducted in the presence of a strong acid or base. The strong acid/base is employed to titrate the weak acid or base sample.

Applications of non-aqueous titration:

• Non-aqueous titration has a wide range of applications, especially in the field of medicine. Some applications of non-aqueous titration are mentioned below.
• Assay and composition analysis of pharmaceutical products is one of the most important applications of non-aqueous titration.
• It is used to know the purity of assays.
• It is employed to determine the concentration expressions.
• A mixture of primary, secondary, and tertiary amines is determined using a non-aqueous titration method.
• Non-aqueous titrations are used to measure the concentration of a certain analyte.
• Non-aqueous titrations can be used to determine the identity of hydrophobic drugs such as diuretics, phenobarbitone, tetracyclines, and steroids, etc,
• It is also used to determine the composition of antitubercular drugs and adrenergic drugs.

Crystal violet, methyl red, naphtholbenzein, quinaldine red, and thymol blue, are some examples of indicators that can be employed in the titration of non-aqueous solutions.

People also ask

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