12635
The results show that , in general , adsorption of phosphopeptides follows the Langmuir model and that the affinity for the TiO ( 2 ) surface increases in a nonlinear fashion with increasing degree of phosphorylation .
 TiO ( 2 )
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 TiO ( 2 )