General Calculation
- Calculation of total column volume (also used for calculating bed volume)
- Calculation of empty column linear flow rate from a volumetric flow rate
- Calculation of volumetric flow rate from empty column linear flow rate
1. Calculation of total column volume (also used for calculating bed volume):
![](https://www.separations.eu.tosohbioscience.com/Image%20Library/TBG/GlobalNav/TECHNICAL%20SUPPORT/Technical%20Support/Technical%20Resources/Chromatography%20Calculations/general_calc_fig1.jpg?code=33ece777-6636-49c7-bf38-29fe9cc68395)
Where:
V = calculated column volume
r = column radius
L = length of the column (or packed bed)
2. Calculation of empty column linear flow rate from volumetric flow rate:
![](https://www.separations.eu.tosohbioscience.com/Image%20Library/TBG/GlobalNav/TECHNICAL%20SUPPORT/Technical%20Support/Technical%20Resources/Chromatography%20Calculations/general_calc_fig2.jpg?code=78b53bab-030b-4c45-98b1-b20207879104)
Where:
u = Linear flow rate (cm/hr)
F = volumetric flow rate (mL/hr) [multiply mL/min x 60 min/hr]
r = column radius (cm)
3. Calculation of volumetric flow rate from empty column linear flow rate
![](https://www.separations.eu.tosohbioscience.com/Image%20Library/TBG/GlobalNav/TECHNICAL%20SUPPORT/Technical%20Support/Technical%20Resources/Chromatography%20Calculations/general_calc_fig3.jpg?code=b53d994d-e663-4f25-b156-884a5ba5703a)
Where:
F = volumetric flow rate (mL/hr) [divide by 60 min/hr to get mL/min]
u = Linear flow rate (cm/hr)
r = column radius (cm)
ALSO READ:Â SOP for HPLC Analysis & Documentation
Pressure Flow Calculations
- Theoretical changes in pressure after changing particle size
- Ergun Modification of the Blake-Kozeny Equation for Pressure-Flow
- Pressure conversions starting with psi
- Pressure conversions starting with bar
- Pressure conversions starting with kg/cm2
- Pressure conversions starting with kPa
- Pressure conversions starting with MPa
1. Theoretical changes in pressure after changing particle size:
![](https://www.separations.eu.tosohbioscience.com/Image%20Library/TBG/GlobalNav/TECHNICAL%20SUPPORT/Technical%20Support/Technical%20Resources/Chromatography%20Calculations/pressureflow_fig1.jpg?code=143220cf-1b2a-4830-8284-0c219f0710fc)
Where: ΔP1 = Initial pressure (any pressure units)
ΔP2 = Calculated pressure (same pressure units as P1)
dp1 = Initial mean particle size (any units but typically µm)
dp2 = Mean particle size of new resin (same units at dp1)
2. Ergun Modification of the Blake-Kozeny Equation for Pressure-Flow:
![](https://www.separations.eu.tosohbioscience.com/Image%20Library/TBG/GlobalNav/TECHNICAL%20SUPPORT/Technical%20Support/Technical%20Resources/Chromatography%20Calculations/pressureflow_fig2.jpg?code=fb4411f7-48c9-4f7c-9051-1fb6711c624d)
Where:
ΔP = Change in pressure
L = Column Length
η = Mobile phase viscosity
u = Empty column linear velocity (cm/hr)
dp2 = Mean particle size
ε = Interstitial void volume intrinsic to each resin
3. Pressure conversions starting with psi:
- To convert to kg/cm2 from psi multiply by 0.0703
- To convert to bar from psi multiply by 0.0690
- To convert to kPa from psi multiply by 6.895
- To convert to MPa from psi multiply by 0.00690
4. Pressure conversions starting with bar:
- To convert to kg/cm2 from bar multiply by 1.0197
- To convert to psi from bar multiply by 14.504
- To convert to kPa from bar multiply by 100
- To convert to MPa from bar multiply by 0.100
5. Pressure conversions starting with kg/cm2: To convert to psi from kg/cm2 multiply by 14.223
- To convert to bar from kg/cm2 multiply by 0.981
- To convert to kPa from kg/cm2 multiply by 98.067
- To convert to MPa from kg/cm2 multiply by 0.0981
6. Pressure conversions starting with kPa: To convert to kg/cm2 from kPa multiply by 0.0102
- To convert to bar from kPa multiply by 0.01
- To convert to psi from kPa multiply by 0.1450
- To convert to MPa from kPa multiply by 0.001
7. Pressure conversions starting with MPa:
- To convert to kg/cm2 from MPa multiply by 10.197
- To convert to bar from MPa multiply by 10
- To convert to kPa from MPa multiply by 1000
- To convert to psi from MPa multiply by 145.04
ALSO READ:Â Maintenance of Flow Cell
Tags
HPLC