Prediction of gas chromatographic retention times of capillary columns of different inside diameters

The retention times ( t   R ) of n ‐alkanes (C 16 –C 22 ) eluted from capillary columns of different diameters are accurately predicted by using the equation proposed by Krisnangkura et al. ( J. Chromatogr. Sci. 1997 , 35 , 329–332). The numerical values of four thermodynamically related constants ( a , b , c , and d ) of the BP‐1 (100% dimethylpolysiloxane) capillary column (0.32 mm ID×25 m, film thickness, 0.25 μm) are –6.169, –0.512, 226.98, and 410.30, respectively. For columns of the same stationary phase but of different inside diameters and film thickness, accurate t R values can be predicted by using the same numerical values of the last three constants but the first constant ( a ) is changed by the difference in the natural logarithm of the column phase ratios (β). All the derived numerical values of each column were tested with FAMEs and with n ‐alkanes in temperature‐programmed GC (TPGC). All the predicted t R values agree well with the experimental values. About 77% of the TPGC data have errors lower than 0.5% and the largest value is –1.04%.