22453
The volatile and semivolatile compounds were extracted , using dynamic headspace extraction ( DHE ) or solid - phase microextraction ( SPME ) and solid phase extraction ( SPE ) , respectively , followed by gas chromatography - mass spectrometry ( GC - MS ) and gas chromatography - olfactometry ( GC - O ) .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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