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: This effect was dose - dependent up to concentrations of 5 X 10 ( - 5 ) M , whereupon blockade of sinus activity set in .
### Output Text:
This effect was dose - dependent up to concentrations of 5 X 10 ( - 5 ) M , whereupon blockade of sinus activity set in . 