Question

Although temperature does not have nearly the effect on HPLC separations that it has on GC separations, it

nonetheless can play an important role. Discuss how and why temperature might or might not influence the

following separations:

(a) a reversed-phase chromatographic separation of a steroid mixture.

(b) an adsorption chromatographic separation of a mixture of closely related isomers.

Short answer

(a) The temperature influences the reverse-phase chromatographic separation of a steroid mixture due to the dependency of factors, such as diffusion rate, and distribution coefficient, on the temperature.

(b) The temperature influences the adsorption chromatographic separation of a mixture of closely related isomers due to the dependency of the factors, such as diffusion rate, and distribution coefficient, on the temperature.

Step-by-step solution

Part (a) Step 1. Given information 

Describe the influence of temperature for a reversed-phase chromatographic separation of a steroid mixture.

Part (a) Step 2. Reversed-phase chromatographic separation of a steroid mixture 

The factors which are responsible for the influence of the HPLC and GC separation are

• Diffusion rate.

• Distribution coefficient.

These all factors depend on the temperature. Therefore, the temperature influences the HPLC and GC separation.

The reverse-phase chromatography is the type of HPLC chromatography. The higher performance liquid chromatography is used for liquid-liquid chromatography. In the higher performance liquid chromatography, both the phases have only liquid solutions.

Therefore, the separation and selectivity of reverse-phase chromatography are influenced by the temperature-dependent factor known as the distribution coefficient. Hence, the temperature influences the reverse-phase chromatographic separation of a steroid mixture.

Therefore, the temperature influences the reverse-phase chromatographic separation of a steroid mixture due to the dependency of the factors, such as diffusion rate, and distribution coefficient, on the temperature.

Part (b) Step 1. Given information 

Describe the influence of temperature for an adsorption chromatographic separation of a mixture of closely related isomers.

Part (b) Step 2. Adsorption chromatographic separation of a mixture 

Adsorption chromatography is the type of GC chromatography. Gas chromatography is also known as gas-solid chromatography in which solid and liquid are present in the stationary phase, and gas is present in the mobile phase.

Therefore, the separation and selectivity of adsorption chromatography is influenced by the temperature-dependent factor known as the distribution coefficient. Hence, the temperature influences the adsorption chromatographic separation of a mixture of closely related isomers.

Therefore, the temperature influences the adsorption chromatographic separation of a mixture of closely related isomers due to the dependency of the factors, such as diffusion rate, and distribution coefficient, on the temperature.