pressure gradient correction factor

in gas chromatography
https://doi.org/10.1351/goldbook.P04821
A factor that corrects for the compressibility of the
carrier gas
. The values of the measured quantities obtained after multiplication by the factor j are independent of the pressure drop in the column. If pi, po are respectively the pressures of the
carrier gas
at the inlet and outlet of the column, then j is given by: j=3 [(pipo)21]2 [(pipo)31]
Source:
Orange Book, 2nd ed., p. 101 [Terms] [Book]