Converting From Linear Fow (cm/hour) to Volumetric Flow Rates (ml/min) and Vice Versa

Appendix 4 extracted from Affinity Chromatography Principles and Methods, GE Healthcare, 2007

It is convenient when comparing results for columns of different sizes to express flow as linear flow (cm/hour). However, flow is usually measured in volumetric flow rate (ml/min).

To convert between linear flow and volumetric flow rate use one of the formulae below.

From linear flow (cm/hour) to volumetric flow rate (ml/min)

 

Volumetric flow rate (ml/min) = Linear flow (cm/h) x column cross sectional area (cm2)
60

 

= Y × π x d2
60 4

where
Y = linear flow in cm/h
d = column inner diameter in cm

Example:
What is the volumetric flow rate in an XK 16/70 column (i.d. 1.6 cm) when the linear flow is 150 cm/hour?
Y = linear flow = 150 cm/h
d = inner diameter of the column = 1.6 cm

Volumetric flow rate (ml/min) = 150 × π × 1.6 x 1.6 ml/min
60 × 4

                                                                = 5.03 ml/min

From volumetric flow rate (ml/min) to linear flow (cm/hour)

Linear flow rate = Volumetric flow rate (ml/min) × 60
column cross sectional area (cm2)

 

= Z × 60 × 4
π x d2

where
Z = volumetric flow rate in ml/min
d = column inner diameter in cm

Example:
What is the linear flow in an HR 5/5 column (i.d. 0.5 cm) when the volumetric flow rate is 1 ml/min?
Z = Volumetric flow rate = 1 ml/min
d = column inner diameter = 0.5 cm

Linear flow = 1 × 60 × 4 cm/h
π x 0.5 x 0.5

                                                                           = 305.6 cm/h

From ml/min to using a syringe

1 ml/min = approximately 30 drops/min on a HiTrap 1 ml column
5 ml/min = approximately 120 drops/min on a HiTrap 5 ml column

Materials

     

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