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: Two subsets of patients were identified from this latter group : the first included four patients ( 5 % of the total population ) who developed major toxicity resulting in Fanconi ' s syndrome ( TDFS ) ; and the second group included five patients with elevated beta 2 microglobulinuria and low phosphate reabsorption .
### Output Text:
Two subsets of patients were identified from this latter group : the first included four patients ( 5 % of the total population ) who developed major toxicity resulting in Fanconi ' s syndrome ( TDFS ) ; and the second group included five patients with elevated beta 2 microglobulinuria and low <span class="chemical">phosphate</span> reabsorption . 