Relationships for modeling the performance of rectangular gas chromatographic columns

Golay's theory for open tubular GC columns was recently revised for application to rectangular GC columns. The HETP was found to be the same as for open tubular columns provided the average linear velocity, ū , and the resistance‐to‐mass‐transfer‐in‐the‐gas‐phase, C M , are redefined. In this paper, a simplified expression for the average linear velocity is derived and used to fit a variety of exit flow data collected on microfabricated rectangular GC columns. Also the resistance‐to‐mass‐transfer‐in‐the‐gas‐phase is studied and the results compared to earlier relationships derived by Giddings, Chang, Myers, Davis and Caldwell, and by Golay. The three theories agree, with the present theory predicting a slightly higher value for C M for large retention indices. The slightly higher value for C M is attributed to the geometry for the rectangular column that is better modeled with the present theory than the former theories.