26492
In the present study , the precursors of DHPG were identified and characterized after extraction from alperujo using thermal treatment and purification by fractionation on Amberlite (R) XAD16 polyamide and semi - preparative reverse - phase HPLC columns .
 DHPG
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 DHPG