21420
The analysis was performed by liquid chromatography coupled to mass spectrometry detection with a quadrupole - time - of - flight analyzer , LC - MS ( QTOF ) , for the identification of nonvolatile substances .
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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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