IMPROVED METHOD FOR COMPUTING TEMPERATURE-PROGRAMMED RETENTION INDEXES FROM ISOTHERMAL DATA

Temperature-programmed retention indices can be rigorously calculated under a single gas chromatography run without any co-injected n-alkane s, using an extension of a concept originally described by Curvers et al. [J. High Resolut. Chromatogr. Chromatogr. Commun., 8 (1985) 607-61 0 and 611-617] and by Akhporhonor et al. [J. Chromatogr. 405 (1987) 67 -76]. The indices are computed from both thermodynamical data, namely Kovats indices, and experimental data (the column gas hold-up time t(0 ) and the phase ratio beta). The two experimental terms can be easily derived, without the need for their exact measurement, if two peaks of the chromatogram are identified. The method was tested to predict the programmed retention indices of a series of monoterpenes. The precisi on of this procedure is consistent with previously published results.