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: All concentrations of nicotine sulfate caused some lethality but a no effect level for coniine lethality was 0 . 75 % .
### Output Text:
All concentrations of <span class="chemical">nicotine</span> sulfate caused some lethality but a no effect level for <span class="chemical">coniine</span> lethality was 0 . 75 % . 