pressure gradient correction factor

in gas chromatography
A factor that corrects for the compressibility of the @[email protected] The values of the measured quantities obtained after multiplication by the factor \(j\) are independent of the pressure drop in the column. If \(p_{\text{i}}\), \(p_{\text{o}}\) are respectively the pressures of the @[email protected] at the inlet and outlet of the column, then \(j\) is given by: \[j=\frac{3\ [(\frac{p_{\text{i}}}{p_{\text{o}}})^{2}- 1]}{2\ [(\frac{p_{\text{i}}}{p_{\text{o}}})^{3}- 1]}\]
Orange Book, 2nd ed., p. 101 [Terms] [Book]