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 discussed. The first is based on a new modification of the correlation equation log RI = a logT_b + bA + c and is recommended for low boiling compounds of the general type R-X with known boiling points (T_b) analyzed on polymer sorbent Porapack Q. The second method permits one to predict RIs of products of organic reactions A + B → C +… with the correlation ΔRI = a ΔE + b (a < 0,|ρ| > 0.9), where ΔRI = RI_C– RI_A– RI_B and ΔE = E_C– E_A– E_B– are the differences in the internal molecular energies of reagents and products of organic reactions which are estimated by molecular dynamics methods. In the final section new possibilities of the use of RIs in reversed phase HPLC, namely for the determination of the number of hydroxyl groups in phenols, are illustrated. Received: 9 November 1998 / Revised: 15 April 1999 / Accepted: 30 April 1999