New applications of the retention index concept in gas and high performance liquid chromatography

New methods for the precalculation of GC retention indices (RIs) are discus sed. The first is based on a new modification of the correlation equation l og RI a logT(b) + bA + c and is recommended for low boiling compounds of th e general type R-X with known boiling points (T-b,) analyzed on polymer sor bent Porapack Q. The second method permits one to predict RIs of products o f organic reactions A + B --> C +... with the correlation Delta RI = a Delt a E + b (a < 0,\rho\ > 0.9), where Delta RI = RIC - RIA - RIB and Delta E = E-C - E-A - E-B - are the differences in the internal molecular energies o f reagents and products of organic reactions which are estimated by molecul ar dynamics methods. In the final section new possibilities of the use of R Is in reversed phase HPLC, namely for the determination of the number of hy droxyl groups in phenols, are illustrated.