26485
One of them was used as marker for quantitative determination on an UPLC / ESI - MS system by using its isotopically labelled analogue as internal standard , allowing to assess the protein content in the different samples .
 None
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:  
Answer:
 None