Question

(a) The interstitial volume, ${\mathbf{V}}_{\mathbf{0}}$, in Figure 26-15 is the volume at which the curves rise vertically at the left. Find${\mathbf{V}}_{\mathbf{0}}$for the 25-nm-pore-size column. To the nearest order of magnitude, what is the smallest molecular mass of molecules excluded from this column? (b) What is the molecular mass of molecules eluted at 9.7 mL from the 12.5-nm column? (c)${\mathbf{V}}_{\mathbf{m}}$is the volume at which the curves drop vertically at the right. Find the largest molecular mass that can freely enter the 45-nm pores.

Short answer

(a)${\mathrm{V}}_0$ for the 25-nm-pore-size column is${\mathrm{V}}_0=5.5$ ml.

The smallest molecular mass of molecules excluded from this column is ${10}^6$Da.

(b) The molecular mass${10}^4$ Da.

(c) The largest molecular mass would be${10}^4$ Da.

Step-by-step solution

Define molecular mass:

Molecule mass is a molecular weight that is equal to the sum of all the atoms contained in a molecule.

Find V0 for the 25-nm-pore-size column:

(a)

Here we will find $V_0$for the 25-nm-pore-size column

The starting point of the curve for 25nm pores which rises vertically at the left would be 11 and end point would be around 5.5 so the ${\mathrm{V}}_0=5.5\mathrm{ml}$ml.

The smallest molecular mass of molecules excluded from this column -${10}^6$ Da.

The molecular mass of molecules eluted at 9.7 mL from the 12.5-nm column:

(b)

Here we will find the molecular mass of molecules eluted at 9.7 mL from the 12.5-nm column.

Look at the Figure 26-15 and find that the molecular mass is${10}^4$ Da.

Find the largest molecular mass:

(c)

Here we will find the largest molecular mass that can freely enter the 45-nm pores

Considering that${\mathrm{V}}_{\mathrm{m}}$ is the volume at which the curves drop vertically at the right - the largest molecular mass would be -${10}^4$ Da.