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 p i, p o are respectively the pressures of the carrier gas at the inlet and outlet of the column, then j is given by: \[j=\frac{3\ [(\frac{p_{\text{i}}}{p_{\text{o}}})^{2}- 1]}{2\ [(\frac{p_{\text{i}}}{p_{\text{o}}})^{3}- 1]}\]*Source: *

Orange Book, 2^{nd} ed., p. 101 (https://media.iupac.org/publications/analytical_compendium/)

Orange Book, 2