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: Glutamate evoked reproducible VAS response to all von Frey gauges ( ICC > 0 . 60 ) and brush strokes ( ICC > 0 . 83 ) .
### Output Text:
<span class="chemical">Glutamate</span> evoked reproducible VAS response to all von Frey gauges ( ICC > 0 . 60 ) and brush strokes ( ICC > 0 . 83 ) . 