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: There was a significant difference among groups in glucose effectiveness ( F ( 30 ) = 4 . 18 ; P = . 02 ) ( clozapine < olanzapine < risperidone ) with significant differences between clozapine and risperidone ( t ( 30 ) = - 2 . 59 ; P = . 02 ) and olanzapine and risperidone ( t ( 30 ) = - 2 . 34 , P = . 03 ) .
### Output Text:
There was a significant difference among groups in <span class="chemical">glucose</span> effectiveness ( F ( 30 ) = 4 . 18 ; P = . 02 ) ( <span class="chemical">clozapine</span> < <span class="chemical">olanzapine</span> < <span class="chemical">risperidone</span> ) with significant differences between <span class="chemical">clozapine</span> and <span class="chemical">risperidone</span> ( t ( 30 ) = - 2 . 59 ; P = . 02 ) and <span class="chemical">olanzapine</span> and <span class="chemical">risperidone</span> ( t ( 30 ) = - 2 . 34 , P = . 03 ) . 