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: Moreover , significant amounts of platinum were detected in the dorsal root ganglia and kidney after CBDCA treatment .
### Output Text:
Moreover , significant amounts of <span class="chemical">platinum</span> were detected in the dorsal root ganglia and kidney after <span class="chemical">CBDCA</span> treatment . 