21186
This process resulted in four distinct MWCNT : raw , purified , - COOH - terminated raw MWCNT , and - COOH - terminated purified MWCNT .
 COOH, COOH
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 COOH, COOH