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Thirteen N - alkylamides were detected in the extract by using HPLC / UV / electrospray ionization mass spectrometry method .
 Chemical: N - alkylamides
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: N - alkylamides