Mosaic increments for predicting the gas chromatographic retention data of the chlorobenzenes

The chlorinated organic compounds are very important from the point of view of the chemical industry and environmental protection, and therefore the gas chromatographic analysis of these compounds is very interesting for analytical chemists. In this paper we studied the relationship between the molecular structure and gas chromatographic retention on several stationary phases having different polarity and at several temperatures of benzene and 12 chlorobenzene compounds as model compounds. A coding system involving primary (mosaic increments) and secondary (bond increments) calculation methods was developed. The retention indices of benzene and the chlorobenzenes calculated on HP-5 at 120 °C shows a better performance of the mosaic increments (average absolute deviation δ of 1.7 retention index units) compared with the bond increments (δ=11.7 retention index units). Retention factors, k, calculated with mosaic increments for chlorobenzenes on SPB-1 and WAX-10, at 140 °C, yield average relative errors of ϵ=0.9 and 3.5%, respectively. Therefore, the presented paper provides a new possibility for precalculation of the retention data.