Hi Raju,
Why dont you attack your issue from a different angle. What I understand you need to send emails to valid IDs only. Correct me if wrong.
Why dont you maintain all your org 's IDs in a Ztable - only verified IDs. Before sending the emails in your code, either select IDs from the table OR verify user entered IDs from this Ztable.
Wont that eliminate your wrong email ID issue?
Regards,
Ags