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: Swallowing - induced atrial tachyarrhythmia triggered by salbutamol : case report and review of the literature .
### Output Text:
Swallowing - induced atrial tachyarrhythmia triggered by <span class="chemical">salbutamol</span> : case report and review of the literature . 