In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: A possible involvement of energy metabolism was suggested previously , and in this study the adenylate energy charge and phosphorylcreatine mole fraction were determined in the adriamycin - treated cells .
### Output Text:
A possible involvement of energy metabolism was suggested previously , and in this study the adenylate energy charge and <span class="chemical">phosphorylcreatine</span> mole fraction were determined in the <span class="chemical">adriamycin</span> - treated cells . 