DETERMINATION OF ETHYLENE-OXIDE IN SPICES USING HEADSPACE GAS-CHROMATOGRAPHY

A method was developed for determining the residues of ethylene oxide (ETO) in dry spices. These residues result from commercial fumigation practices to control insect pests. The analytical method makes use of a headspace gas chromatograph, equipped with a porous layer open tubul ar (PLOT) megabore column, and sealed 22 mt headspace vials containing 1 g aliquots of the spices. The spice samples, containing added 1-oct anol, are thermostated for 20 min at a temperature of 60 degrees C pri or to injection of microliter aliquots of the equilibrated headspace. By holding the PLOT column at 70 degrees C, ETO will elute in about 8 min, after which time the column is heated at 30 degrees C/min to 220 degrees C, at which the temperature is held for 5 min to clear the col umn for the next injection. On the basis of spice matrix standards, re coveries of ETO from a variety of different spices fell in the range 7 5-130% (av = 100%, n = 120) for spiking levels covering the range 1-10 00 ppm. The practical limit of detection was 1 ppm. By using an automa ted headspace instrument, it is possible to analyze over 60 samples in a 24-h period.