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: Plasma apolipoprotein A - I was found not only in HDL ( 1 . 063 - 1 . 210 g / ml ) but also in the LDL density class ( 1 . 025 - 1 . 050 g / ml ) .
### Output Text:
Plasma apolipoprotein A - I was found not only in HDL ( 1 . 063 - 1 . 210 g / ml ) but also in the LDL density class ( 1 . 025 - 1 . 050 g / ml ) . 