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: In addition , the endothelial permeability and the penetration through the aortic wall of albumin were studied 10 minutes , 24 and 48 hours after i . v . injection of human serum 131I - albumin ( 131I - HSA ) .
### Output Text:
In addition , the endothelial permeability and the penetration through the aortic wall of albumin were studied 10 minutes , 24 and 48 hours after i . v . injection of human serum 131I - albumin ( 131I - HSA ) . 