9141
In this study , we developed a robust and sensitive liquid chromatography - tandem mass spectrometry method for the analysis of 4 - hydroxy - 1 - ( 3 - pyridyl ) - 1 - butanone ( HPB ) - releasing DNA adducts in human oral cells , a noninvasive source of DNA for biomarker studies .
 Chemical: 4 - hydroxy - 1 - ( 3 - pyridyl ) - 1 - butanone; Chemical: HPB
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: 4 - hydroxy - 1 - ( 3 - pyridyl ) - 1 - butanone, HPB 
Answer:
 Chemical: 4 - hydroxy - 1 - ( 3 - pyridyl ) - 1 - butanone; Chemical: HPB