Given the task definition, example input & output, solve the new input case.
In this task, you are given a sentence. You are expected to recognize the name of any form of chemical substances. Although there might be several correct answers, you need to write one of them.
Example: Inhibition of the human ether-a-go-go-related gene (HERG) potassium channel by cisapride: affinity for open and inactivated states. 
Output: potassium
 Potassium is a type of electrolyte mineral that helps our nerves to function and muscles to contract. Hence, it should be tagged as chemical.

New input case for you: Desvenlafaxine succinate identifies novel antagonist binding determinants in the human norepinephrine transporter.
Output:
norepinephrine