Abstract: Ultrasonic extraction-GC of hexachlorobenzene in plant food was studied in this paper. Results showed that the degradation rate of hexachlorobenzene in different treatments of ultrasonic extraction was very low. The best ultrasonic extraction conditions were as follows: power 20W, temperature 35℃, time 60min and the mixture of petroleum ether and acetone (1:1) as solvent. Under the best ultrasonic extraction conditions, the average recovery of hexachlorobenzene in samples was 90.80%, CV 2.23% and the detection limits 0.0001μg /g.

Key words: ultrasonic extraction, plant food, hexachlorobenzene, trace organic contamination