DRAFT: This module has unpublished changes.

Calculations:

 

For each trial, calculate the VM, the mobile phase volume:

 

Trial 1:

 

VM = 0.5 πr2L = 0.5 x 3.14 x (0.50 cm)2 x 1.8 cm = 0.707 mL

 

Trial 2:

 

VM = 0.5 πr2L = 0.5 x 3.14 x (0.50cm)2 x 3.5cm = 1.37 mL

 

For each trial, calculate the band width for the two components:

 

Trial 1:

 

VR(start, red) = 1.2 mL

VR(end, red) = 1.3 mL

 

VR(start, blue) = 1.35 mL

VR(end, blue) = 2.0 mL


W(red)= VR(end, red) – VR(start, red) = 1.3 mL - 1.2 mL = 0.1 mL

 

W(blue)=VR(end, blue) – VR(start, blue) = 2.0 mL - 1.35 mL = 0.65 mL

 

Trial 2:

 

VR(start, red) = 1.8 mL

VR(end, red) = 2.3 mL

 

VR(start, blue) = 2.3 mL

VR(end, blue) = 4.3 mL

 

W(red)= VR(end, red) – VR(start, red) = 2.3 mL – 1.8 mL = 0.5 mL

 

W(blue)=VR(end, blue) – VR(start, blue) = 4.3 mL – 2.3 mL = 2.0 mL

 

For each trial, calculate the center of the bands for the two components:

 
Trial 1:

 

VR(avg, red) = VR(start, red) + 0.5 Wred= 1.2 mL + (0.5)(0.1 mL) = 1.25 mL

VR (avg, blue) = VR(start, blue) + 0.5 Wblue= 1.35 mL + (0.5)(0.65 mL) = 1.675 mL

 

Trial 2:


VR(avg,red) = VR(start, red) + 0.5 Wred= 1.8 mL + (0.5)(0.5 mL) = 2.05 mL

VR (avg, blue) = VR(start, blue) + 0.5 Wblue= 2.3 mL + (0.5)(2.0 mL) = 3.3 mL

 

For each tiral, calculate the retention factor k' for both components:

 

Trial 1:

 

k red’ = (VR(avg, red) - VM) = (1.25 mL – 0.707 mL) = 0.77 mL
                       (VM)                         (0.707 mL)


k blue’ = (VR(avg, blue) - VM) = (1.675 mL – 0.707 mL) = 1.37 mL
                      (VM)                        (0.707 mL)

 

Trial 2:

 

k red’ = (VR(avg, red) - VM) = (2.05 mL – 1.37 mL) = 0.50 mL
                      (VM)                          (1.37 mL)


k blue’ = (VR(avg,blue) - VM)  = (3.3 mL – 1.37 mL) = 1.41 mL
                       (VM)                           (1.37 mL)

 

For each trial, calculate the selectivity, or seperation factor, a:

Trial 1:

 

a = k’ blue = 1.37  = 1.78

      k' red     0.77

 

Trial 2:

 

a = k’ blue = 1.41 = 2.83
      k' red      0.50

 

For each trial, calculate the number of theoretical plates, N, in the column:

 

Trial 1:

 

N = 16 [(VR(end,blue)]2 = 16 [2 mL]2 = 49.23 mL
                 [Wblue]                [0.65 mL]

 


Trial 2:

N = 16[VR(end,blue)]2 = 16[4.3 mL]2 = 34.4 mL
               [Wblue]                [2.0 mL]

 

For each trial, calculate the resolution R, the major objective of a chromatographic seperation:

 

Trial 1:

 

R = 2(VR (avg, blue) - VR(avg,red)) = 2(1.675 mL – 1.25 mL) = 1.133 mL
                Wred + Wblue                         (0.1 mL + 0.65 mL)

Trial 2:


R = 2(VR (avg, blue) - VR(avg,red)) = 2(3.3 mL – 2.05 mL) = 7.0 mL

                Wred + Wblue                      (4.3 mL + 2.0 mL)

 

Calculate the average values for a, N, and R:

 

a = (trial 1 + trial 2) = (1.78 + 2.82) = 2.3
                 2                          2


N = (trial 1 + trial 2)  = (49.23 + 34.4) = 41.82

                  2                            2

R = (trial 1 + trial 2) = (1.133 + 7.0) = 4.17

                  2                           2

 

DRAFT: This module has unpublished changes.