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: Anemia was induced using a single dose of carboplatin ( 50 mg / kg i . v . ) resulting in a long - lasting reduction ( 30 % ) of the hemoglobin concentration .
### Output Text:
Anemia was induced using a single dose of <span class="chemical">carboplatin</span> ( 50 mg / kg i . v . ) resulting in a long - lasting reduction ( 30 % ) of the hemoglobin concentration . 