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: Captopril had little or no demonstrable effects on serum electrolyte concentrations , excretion of urine , sodium and potassium , endogenous creatinine clearance , body weight , and food and water consumption .
### Output Text:
<span class="chemical">Captopril</span> had little or no demonstrable effects on serum electrolyte concentrations , excretion of urine , <span class="chemical">sodium</span> and <span class="chemical">potassium</span> , endogenous <span class="chemical">creatinine</span> clearance , body weight , and food and water consumption . 