Gas Chromatography - Gas Supplies > Flow Programmers > Page 9
Flow Programmers
Flow programming is a procedure where the mobile phase flow-rate is increased during chromatographic development. If the mobile phase is compressible the relationship between retention volume, flow rate and inlet pressure is given by,
(1)
Where (Vr) | is the true retention volume of the solute, |
(Vr(0)) | is the retention volume measured at the outlet. |
and (g) | is the inlet/outlet pressure ratio |
(for the derivation of this equation see The Thermodynamics of Chromatography)
Thus,
Now, from
The Thermodynamics of Chromatography
where (e) is a constant
Thus, (2)
If (g) is large compared with unity, Then