91影视

A chromatography column in which the stationary phase is either the inner tube wall or a liquid or active material held stationary on the tube wall, while

the mobile phase has an open, unrestricted route.

(a)

The Deemter equation is given as,

$H鈮�A+\frac{B}{u{x}_x}+C{u}_x$

$C{u}_x$is equilibration time

Using the Deemter equation, the term for an open tubular column is found to be zero. The letter A denotes the many options available. In a packed column, the multiple plat begins when the liquid flow follows various paths through the column.

(b)

The Deemter equation is written as follows:

$HA+Bx+Cux+Cux$

WhereA denotes multiple paths.

$\frac{B}{uz}$

Longitudinal diffusion is denoted by the symbol Cux.

To express the worth ofin terms of a physical attribute that can be measured

In terms of measurable physical property, the term B can be expressed as,$B=2D_m$,

where${\mathrm{D}}_{\mathrm{m}}$ = diffusion coefficient of solute in mobile phase

(c)

The Deemter equation is given as,

$\mathrm{H}鈮�\mathrm{A}+\frac{\mathrm{B}}{{\mathrm{U}}_{\mathrm{x}}}+{\mathrm{Cu}}_{\mathrm{x}}$

Where A is multiple paths

$\frac{B}{u_s}$is Longitudinal diffusion

$C{u}_x$is equilibration time

To give the value of C in terms of measurable physical property

In terms of measurable physical property, the term C can be expressed as,

$C=C_s+C_m$

role="math" localid="1664886662003" $$\begin{gathered} Here,C_s=\frac{2k}{3{\left(k+1\right)}^2}\frac{d^2}{D_s} \\ {C}_m=\frac{1+6k+11k^2}{24{\left(k+1\right)}^2}\frac{r^2}{D_m} \end{gathered}$$

where$D_m$ = diffusion coefficient of solute in mobile phase

k= retention factor

d= thickness of stationary phase

r= radius of column

$D_S=$diffusion coefficient of solute in stationary phase

(d)

The Deemter equation is given as,

$H鈮�A+\frac{B}{u_x}+C{u}_x$

Where A is multiple paths

$\frac{B}{u_z}$is Longitudinal diffusion

$C{u}_x$is equilibration time

To give an for the minimum plate height in terms of measurable physical quantities of B and C

$H=\frac{B}{u_x}+C{u}_x$

Where$u_x=$ linear velocity

At optimum velocity, the plate height is minimum

$$\begin{gathered} \frac{dH}{d{u}_x}=-\frac{B}{u_{s^2}}+c=0 \\ {u}_x=\sqrt{\frac{B}{C}} \end{gathered}$$

The minimum height of the plate is estimated by substituting the values of$u_x$ (optimum) back into the van Deemter equation,

$$\begin{gathered} H_{min}=\frac{B}{u_x^2}+C{u}_x \\ =B\sqrt{\frac{C}{B}}+C\sqrt{\frac{B}{C}} \\ \sqrt{BC}=2\sqrt{B+\left(C_s+C_m\right)} \\ {H}_{min}=2\sqrt{\left(2D_m\right)\left(\frac{2k}{3{\left(k+1\right)}^2}\frac{d^2}{D_s}+\frac{1+6k+11k}{24{\left(k+1\right)}^2}\frac{r^2}{D_m}\right)} \\ {H}_{min}=2\sqrt{\frac{4K}{3{\left(k+1\right)}^2}\frac{d^2{D}_m}{D_s}+\frac{\left(1+6k+11k\right)2_r^2}{24{\left(k+1\right)}^2}} \end{gathered}$$

Thus the minimum plate height is $H_{min}=2\sqrt{\frac{4K}{3{\left(k+1\right)}^2}\frac{d^2{D}_m}{D_s}+\frac{\left(1+6k+11k\right)2_r^2}{24{\left(k+1\right)}^2}}$.