9855
EC50 estimation of antioxidant activity in DPPH . assay using several statistical programs .
 Chemical: DPPH .
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: DPPH . 
Answer:
 Chemical: DPPH .