18830
The chromatographic separation was performed on a reverse phase C18 column with a mobile phase consisting of 0 . 1 % formic acid and acetonitrile ( 45 : 55 , v / v ) at a flow rate of 0 . 3 mL / min .
 formic acid, acetonitrile
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 formic acid, acetonitrile