Nature of the Olefines produced by Apples

Abstract

DURING the past few months, we have been using gas chromatography for the routine analysis of ethylene in air samples from fruit stores (unpublished results; see also Nature of September 26, p. 995) A long column is used in order to separate the ethylene from other hydrocarbons of low boiling-point, and under our experimental conditions, using a flame ionization detector, the lower limit of detection for ethylene in a 0.5 ml. sample of air is about 0.3 mµgm. This represents a sensitivity at least 1,000 times greater than we obtained with a katharometer detector used previously. In order to detect other hydrocarbons which might be produced by apples in much smaller quantities, large samples of air from apple stores were passed through a U-tube fitted with a sintered plate or filled with glass wool and cooled in liquid oxygen. The condensates were then liberated on to the chromatography column.