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: Risks of the consumption of beverages containing quinine .
### Output Text:
Risks of the consumption of beverages containing <span class="chemical">quinine</span> . 