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: Intravenous hydration and mannitol was administered before and after cisplatin .
### Output Text:
Intravenous hydration and <span class="chemical">mannitol</span> was administered before and after <span class="chemical">cisplatin</span> . 