The hold-up time in gas chromatography .2. Validation of the estimation based on the concept of a zero carbon atoms alkane

The procedure of estimating the hold-up time in gas chromatography recently presented by Lebron-Aguilar et al. [J. Chromatogr. A, 760 (1997) 219] as the retention of an alkane of zero carbon atoms has been exhaustively tested with packed and capillary columns of various stationary phase types, between 30 and 150 degrees C. Several permanent gases injected have shown that there is not a general rule to decide which is the least retained gas under all circumstances. Results of hold-up times obtained with the new procedure have been compared with those of other well established methods. The conclusion arrived at is that the retention of an n-alkane of n carbon atoms is best described by the expression: t(R) (n)=A+exp(B+C n(D)), and the best estimation of the hold-up time is obtained from that expression for n=0.