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: Therefore , the effect of bis ( p - nitrophenyl ) phosphate ( BNPP ) , an acylamidase inhibitor , on APAP and PAP nephrotoxicity and metabolism was determined .
### Output Text:
Therefore , the effect of <span class="chemical">bis ( p - nitrophenyl ) phosphate</span> ( <span class="chemical">BNPP</span> ) , an acylamidase inhibitor , on <span class="chemical">APAP</span> and <span class="chemical">PAP</span> nephrotoxicity and metabolism was determined . 