ANALYSIS OF HALOALKANES ON WIDE-BORE CAPILLARY COLUMNS OF DIFFERENT POLARITY CONNECTED IN SERIES

Thirty chloro-, bromo- and iodo-methanes, -ethanes and -ethenes, with one or more identical or different halogen atoms in the molecule, that can be present as contaminants in polluted surface or underground water were separated by using non-polar (SPB-1) and polar (Supelcowax-10) wide-bore capillary columns connected in series. Retention times and indices were measured at different temperatures and carrier gas flow-rates. The most efficient combination was obtained by connecting the two columns in the order non-polar + polar, which permitted the complete resolution of 26 compounds, while two were partially separated and two were co-eluted. The non-polar column alone co-eluted nine, the polar column eight and the polar + non-polar arrangement four compounds. The polarity of the coupled columns system was evaluated by using Rohrschneider and McReynolds constants with respect to various polarity probes, and by comparison of the slopes and intercept values of the straight lines obtained by plotting the retention values of various homologous series of compounds as a function of the number of carbon atoms in the molecule. © 1990.