This question could be asking two questions. How do you scrape a b2b email marketing list, or how do I find a one of email address for a targeted email.

With regards to scraping a list, this is fraught with the possibility of killing your deliverability. It is so easy to add a spam trap. It might me much easier to have people mail on your behalf with a call to action on a squeeze page to join your list.

If you are looking for targeted names for sales people to email one on one I find hunter.io a very useful too.

Goodluck.

Mick