Terms Used in Formula:
- Tg2 = Tg1 x (Fc1/Fc2) x ((Dc22) / (Dc12)) x (Lc2 x Lc1)
Here is an example problem to solve for.
If we start with a flow rate of 1.000 mL/min (Fc1) on a 4.6 x 250 mm column with 5 micron support (Dc1 & Lc1) and have an initial Gradient Time of 10 minutes (Tg1), then what would the new gradient time be if we switched to a sub 2 micron support in a 2.1 x 50 mm column (Dc2 & Lc2) at 0.200 mL/min (Fc2)?
To solve the equation we will plug-in the values for each part of the equation separately, then multiply them to obtain the result.
(Fc1/Fc2): 1.000/0.200 = 5
(Dc22) / (Dc12) 4.41/21.16 = 0.21
(Lc2 x Lc1) = 50/250 = 0.20
Tg2 = 10 x 5 x 0.21 x 0.20
Tg2 = 2.10 (or 2.10 minutes)
If a 2.1 x 50 mm column was substituted for the 4.6 x 250 mm AND the flow rate was changed from 1.000 mL/min to 0.200 mL/min, then the initial programmed gradient time of 10 minutes would be changed to 2.1 minutes