Chapter 22, Problem 22.11P

(a)

Interpretation Introduction

Interpretation:

Requirement of high pressure in HPLC has to be explained.

Concept Introduction:

High performance liquid chromatography in analytical chemistry is an important technique for the separation, identification, and quantification of analyte. Previously high-performance liquid chromatography was known as high-pressure liquid chromatography.

(b)

Interpretation Introduction

Interpretation:

Reason behind the increase in efficiency of liquid chromatography with decrease in particle size of the stationary phase has to be explained.

Concept Introduction:

Plate height can be calculated by van Deemter equation as follows:

    $\text{H}\approx \text{A}+\frac{\text{B}}{\text{u}}+\left(\text{C}\right)\left(\text{u}\right)$

Here $\text{H}$ is the plate height.

$\text{A}$ term is the eddy diffusion constant.

$\text{B}$ term is the longitudinal diffusion constant.

$\text{C}$ term is the mass transfer constant.

$\text{u}$ is flow rate.

The term $\text{A}$ that is the eddy diffusion constant is related to the particle size of the packing material and uniformity of the flow around the particles. Still, it is independent of the flow rate.

The term $\text{B}$ that is the longitudinal diffusion is related to the diffusion of the analyte in the mobile phase and on the stationary phase.

The term $\text{C}$ that is the mass transfer constant is related to the linear velocity and the square of the particle size.

Plate height is inversely proportional to the efficiency of the chromatographic separation.

(b)

Interpretation Introduction

Interpretation:

Advantages and disadvantages of UPLC have to be explained.

Concept Introduction:

Ultra performance liquid chromatography is a modification over HPLC. It is applicable for particles with less than $\text{2}\text{μm}$ diameter. It produces better speed, sensitivity and resolution over the HPLC.

(d)

Interpretation Introduction

Interpretation:

Advantages of the use of superficially porous particle has to be written.

Concept Introduction:

In superficially porous particle chromatography, stationary phase diffuses into fully porous particles with a radius of $\text{2}\text{.5}\text{μm}$. Thus enabling high chromatographic efficiency at high flow rate.