In order to obtain the best chromatographic conditions, retention times and separation profile of the compounds in study were monitored. Thus, the conditions utilized for the GC-ECD system were: injector model 1079 operating with programmed temperature vaporization (PTV) under the following temperature conditions: 100 ºC for 0.1 min and then increased at 200 °C min-1 to 280 °C which was held for 28 min.