Chapter 21, Problem 21.19P

(a)

Interpretation Introduction

Interpretation:

Plate height has to be calculated.

Concept Introduction:

Expression to compute plate height by van Deemter equation is as follows:

  $H=A+B\text{/}u+Cu$

Here,

$A$ denotes coefficient of eddy diffusion.

$\text{B}$ denotes coefficient of longitudinal diffusion.

$C$ denotes coefficient of mass transfer.

$u$ denotes linear velocity of the mobile phase $\text{mL/min}$.

$H$ denotes plate height in $\text{mm}$.

(b)

Interpretation Introduction

Interpretation:

Number of plates has to be calculated on the column.

Concept Introduction:

Expression to compute number of plates from $H$ is as follows:

  $N=\frac{L}{H}$

Here,

$N$ denotes number of theoretical plate.

$L$ denotes length of chromatographic column.

$H$ denotes plate height.

(c)

Interpretation Introduction

Interpretation:

Value of $w_{1/2}$ has to be calculated.

Concept Introduction:

Expression to compute $w_{1/2}$ from number of theoretical plate is as follows:

  $w_{1/2}={\left(\frac{5.55t_{\text{r}}{}^2}{N}\right)}^{1/2}$

Here,

$t_{\text{r}}$ denotes analyte’s  retention time.

$w_{1/2}$ denotes peak width at half-height.

$N$ denotes number of theoretical plate.