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: CASE : A 58 - year - old man received an intracarotid injection of carboplatin for recurrent glioblastomas in his left temporal lobe .
### Output Text:
CASE : A 58 - year - old man received an intracarotid injection of <span class="chemical">carboplatin</span> for recurrent glioblastomas in his left temporal lobe . 