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: These results demonstrate a neutrophil defect in ALF due to paracetamol overdose , that is complement dependent but independent of serum complement , possibly connected to the complement receptor .
### Output Text:
These results demonstrate a neutrophil defect in ALF due to <span class="chemical">paracetamol</span> overdose , that is complement dependent but independent of serum complement , possibly connected to the complement receptor . 